Anatomy of Flowering Plants (NCERT Practice Paper)

Q1. All tissues except epidermis and vascular bundles constitute the:

Correct Answer: (b)
The ground tissue system includes all tissues other than epidermis and vascular bundles. It comprises cortex, pericycle, medullary rays, pith and mesophyll. It is responsible for storage, photosynthesis and mechanical support. It is the most extensive tissue system in the plant body, filling the spaces between epidermis and vascular tissues.

Q2. Stomata occur mainly in the:

Correct Answer: (c)
Stomata are pores found primarily in the epidermis of leaves, though they may also occur on stems and other aerial parts. They are surrounded by guard cells and are responsible for gas exchange (CO₂ intake and O₂ release) and transpiration. In dicot leaves, stomata are more abundant on the lower (abaxial) surface, while in monocots they may be equally distributed.

Q3. In isobilateral (monocot) leaves, stomata are present:

Correct Answer: (c)
Isobilateral leaves (typical of monocots) have stomata on both the upper and lower epidermis. This allows efficient gas exchange regardless of leaf orientation. The mesophyll is not differentiated into palisade and spongy layers. This contrasts with dorsiventral leaves where stomata are mainly on the lower surface.

Q4. In a young dicot stem, the outermost protective layer is:

Correct Answer: (c)
In young dicot stems, the epidermis is the outermost protective layer. It is usually single-layered, with cuticle and sometimes trichomes. As the stem ages, the epidermis may be replaced by periderm (cork) during secondary growth. The hypodermis lies below the epidermis, and pericycle is part of the stele.

Q5. Monocotyledonous roots do NOT normally undergo:

Correct Answer: (b)
Monocot roots lack cambium, so they do not undergo secondary growth (increase in girth). They do undergo primary growth (elongation) and form root hairs. Primary thickening may occur in some monocots but is not typical secondary growth. The absence of secondary growth is a key difference from dicot roots.

Q6. Study of the internal structure of plants is called:

Correct Answer: (c)
Plant anatomy is the study of the internal structure and functional organisation of higher plants. It focuses on the arrangement of tissues and cells within organs like roots, stems and leaves. This discipline helps us understand how plants are built to perform specific functions. It is distinct from morphology, which deals with external features.

Q7. Vascular bundles in dicot leaves are surrounded by a layer of:

Correct Answer: (b)
In dicot leaves, vascular bundles are surrounded by a bundle sheath made of thick-walled cells, often parenchymatous but sometimes sclerenchymatous. This sheath may be involved in the Calvin cycle (Kranz anatomy) in some plants, though that is more typical of C4 plants. The bundle sheath provides protection and structural support.

Q8. The epidermis covering the upper surface of a dicot leaf is termed:

Correct Answer: (b)
The upper surface of a dorsiventral leaf is the adaxial (or dorsal) surface, and its epidermis is called adaxial epidermis. The lower surface is abaxial. This terminology is used to describe leaf orientation. The adaxial epidermis often has fewer stomata compared to abaxial.

Q9. Regarding dorsiventral dicot leaves, which statements are correct?
(i) Abaxial epidermis usually has more stomata.
(ii) Mesophyll is differentiated into palisade and spongy parenchyma.
(iii) Bundle sheath surrounds the vascular bundles.

Correct Answer: (d)
All three statements are correct for dicot leaves: abaxial epidermis has more stomata (i), mesophyll is differentiated (ii), and vascular bundles have a bundle sheath (iii). These are standard anatomical features.

Q10. The innermost layer of cortex in roots is called:

Correct Answer: (c)
The innermost layer of the cortex is the endodermis. It is a single layer of cells with Casparian strips (suberin deposition) on radial and tangential walls. It regulates the movement of water and minerals into the vascular cylinder. In stems, the endodermis is often called the starch sheath if it stores starch.

Q11. Spongy parenchyma in dicot leaf is characterised by:

Correct Answer: (b)
Spongy parenchyma consists of oval or irregularly shaped cells with large intercellular spaces (air cavities). These spaces facilitate gaseous exchange (CO₂, O₂) within the leaf. The cells are loosely arranged, unlike the compact palisade. They contain fewer chloroplasts than palisade but still photosynthesise.

Q12. Pith in monocot roots is:

Correct Answer: (b)
In monocot roots, the pith is large and well developed, consisting of parenchymatous cells. This contrasts with dicot roots where pith is small or absent. The large pith in monocot roots provides storage and mechanical support. It is a characteristic feature of monocot root anatomy.

Q13. Assertion: Monocotyledonous roots do not show secondary growth. Reason: Their vascular bundles lack cambium.

Correct Answer: (a)
Both assertion and reason are true. Monocot roots lack cambium, so they cannot produce secondary xylem and phloem, hence no secondary growth. The absence of cambium is the direct cause of the lack of secondary growth. The reason correctly explains the assertion.

Q14. In a typical dicot leaf, more stomata are present on:

Correct Answer: (b)
In dicot leaves, stomata are usually more numerous on the abaxial (lower) epidermis. This reduces water loss from direct sunlight and helps in efficient gas exchange. The upper epidermis often has fewer stomata. This is a common adaptation to reduce transpiration while maintaining CO₂ uptake.

Q15. The central region of dicot stem, occupied by rounded parenchymatous cells with intercellular spaces, is the:

Correct Answer: (b)
The pith is the central region of a dicot stem, composed of parenchymatous cells with intercellular spaces. It often stores food and may be involved in support. It is located inside the vascular ring. In monocots, pith is often absent or reduced, and ground tissue is not differentiated into cortex and pith.

Q16. In flowering plants, cells are organised into tissues, and tissues into:

Correct Answer: (b)
Cells form tissues, which are then organised into organs such as roots, stems, leaves and flowers. Organs are the structural units that perform specific functions. This hierarchical organisation allows for division of labour within the plant body. Tissues are groups of similar cells performing a common function.

Q17. Regarding dicot stems, which statements are correct?
(i) Vascular bundles are arranged in a ring.
(ii) Each vascular bundle is conjoint and open.
(iii) Endodermis is rich in starch grains.

Correct Answer: (d)
All three statements are correct for dicot stems: bundles are in a ring (i), they are conjoint and open (ii), and the endodermis acts as a starch sheath (iii). These are typical features of dicot stem anatomy.

Q18. The epidermal tissue system forms the:

Correct Answer: (b)
The epidermal tissue system is the outermost layer of the primary plant body. It provides protection against water loss, mechanical injury and pathogen entry. It is a continuous layer covering roots, stems, leaves and flowers. Its cells are typically parenchymatous and may bear cuticle, stomata and trichomes.

Q19. Epidermis of the primary plant body is usually:

Correct Answer: (b)
The epidermis is typically a single layer of compactly arranged cells forming a continuous covering. This arrangement provides a protective barrier. In some cases, it may become multilayered (e.g., in Ficus leaves), but the general pattern is single-layered. The cells are living and often vacuolated, with a thin cuticle on aerial parts.

Q20. Assertion: Ground tissue system forms the main bulk of the plant. Reason: Ground tissue includes cortex, pericycle and pith in many organs.

Correct Answer: (a)
Both assertion and reason are true. The ground tissue system indeed constitutes the major portion of the plant body, filling the regions between epidermis and vascular bundles. It includes cortex, pericycle, medullary rays, pith and mesophyll. The reason correctly identifies components of ground tissue, thereby explaining why it forms the bulk.

Q21. Ground tissue consists mainly of which simple tissues?

Correct Answer: (a)
Ground tissue is made up of simple tissues: parenchyma (for storage and photosynthesis), collenchyma (for flexible support) and sclerenchyma (for rigid support). These are the basic tissue types that form the bulk of the plant. Complex tissues like xylem and phloem are vascular, not ground. Epidermis is a separate system.

Q22. A major function of trichomes on the shoot is:

Correct Answer: (c)
Trichomes help reduce water loss by trapping a layer of moist air near the leaf surface, thereby lowering the rate of transpiration. They also reflect sunlight, reducing heating. Some trichomes provide protection against herbivores by being stiff or glandular (secreting irritants). They do not fix nitrogen, disperse seeds (though some may aid) or conduct food.

Q23. The medullary rays in dicot stems are formed of:

Correct Answer: (a)
Medullary rays are radial strips of parenchyma cells that connect the pith to the cortex, passing between vascular bundles. They are radially oriented and allow lateral transport of water and food. They are living parenchymatous tissues. They are not sclerenchymatous, nor are they xylem or phloem elements.

Q24. Lateral roots and vascular cambium during secondary growth in dicot roots originate from:

Correct Answer: (b)
Lateral roots originate from the pericycle, which is a meristematic layer. Vascular cambium also arises from the pericycle (and conjunctive tissue) during secondary growth. The pericycle is therefore a crucial tissue for root branching and thickening. The endodermis and pith do not give rise to these structures.

Q25. Each vascular bundle in dicot stem is:

Correct Answer: (b)
Dicot stem vascular bundles are conjoint (xylem and phloem together), open (have cambium), and endarch (protoxylem towards centre). This arrangement permits secondary growth. They are arranged in a ring. The protoxylem is innermost (endarch) in stems, contrasting with roots where it is exarch.

Q26. Regarding isobilateral monocot leaves, which statements are correct?
(i) Stomata are present on both surfaces of the leaf.
(ii) Mesophyll is not differentiated into palisade and spongy.
(iii) Bulliform cells occur in abaxial epidermis along the veins.

Correct Answer: (a)
Statements (i) and (ii) are true for monocot leaves: stomata on both surfaces and undifferentiated mesophyll. However, bulliform cells are located in the adaxial (upper) epidermis, not abaxial (iii is false). Therefore, only (i) and (ii) are correct.

Q27. Each vascular bundle in monocot stem is surrounded by:

Correct Answer: (c)
In monocot stems, each vascular bundle is enclosed by a sclerenchymatous bundle sheath made of thick-walled fibres. This sheath provides mechanical support and protection. It is a characteristic feature of monocot stems. The bundle sheath may also be parenchymatous in some cases, but typically it is sclerenchymatous.

Q28. In monocot stem, which tissue is absent from phloem?

Correct Answer: (c)
Phloem parenchyma is typically absent in monocot stems. The phloem consists of sieve tubes and companion cells; phloem fibres may be present. The absence of phloem parenchyma is a characteristic of monocot phloem. In dicots, phloem parenchyma is commonly present.

Q29. Vascular bundles in monocot stem are:

Correct Answer: (b)
Vascular bundles in monocot stems are conjoint (xylem and phloem together) and closed (no cambium). They are scattered and have a sclerenchymatous sheath. The absence of cambium means no secondary growth. This is a distinguishing feature from dicot stems which have open bundles.

Q30. Root hairs are:

Correct Answer: (b)
Root hairs are unicellular extensions of the epidermal cells (epiblema) in the region of maturation of roots. They are not multicellular. They greatly increase the surface area for absorption of water and minerals. Root hairs are short-lived and are replaced as the root grows. They are not lignified and are thin-walled to facilitate absorption.

Q31. In leaves, the ground tissue consisting of thin-walled chloroplast-containing cells is called:

Correct Answer: (c)
In leaves, the ground tissue is called mesophyll. It is composed of parenchymatous cells with many chloroplasts, specialised for photosynthesis. In dicot leaves, it is differentiated into palisade and spongy parenchyma. In monocot leaves, it is often undifferentiated. Mesophyll is the primary site of photosynthesis in leaves.

Q32. Match the organ type with its leaf anatomy:

Column-I	Column-II
A. Dorsiventral leaf	(I) Mesophyll differentiated into palisade and spongy parenchyma
B. Isobilateral leaf	(II) Mesophyll not differentiated; stomata on both surfaces

Correct Answer: (a)
Dorsiventral leaves (dicots) have mesophyll differentiated into palisade and spongy parenchyma (I). Isobilateral leaves (monocots) have undifferentiated mesophyll and stomata on both surfaces (II). The correct matching is A-I, B-II.

Q33. The three main parts seen in vertical section of a dorsiventral (dicot) leaf are:

Correct Answer: (b)
A vertical section of a dorsiventral leaf shows three main parts: epidermis (upper and lower), mesophyll (photosynthetic tissue), and vascular system (veins). Cortex and pith are root/stem tissues, not leaf. The leaf does not have endodermis or pericycle as distinct layers. The cuticle is part of epidermis.

Q34. Function of hypodermal collenchyma in dicot stems is mainly:

Correct Answer: (c)
Hypodermal collenchyma provides mechanical strength and flexibility to the young growing stem. Its cells are living and have thickened primary walls, allowing them to stretch as the stem elongates. They do not conduct water (xylem) or photosynthesise extensively, though they may contain chloroplasts. Storage is mainly in parenchyma.

Q35. Assertion: Conjoint vascular bundles are common in stems and leaves. Reason: In such bundles, xylem and phloem are jointly situated along the same radius.

Correct Answer: (a)
Both statements are true. Conjoint bundles, where xylem and phloem are on the same radius, are typical of stems and leaves. The reason defines conjoint bundles, and this arrangement is indeed the basis for their common occurrence in these organs. Thus, the reason correctly explains the assertion.

Q36. Which of the following is NOT a basic tissue system of flowering plants?

Correct Answer: (d)
The three basic tissue systems are epidermal, ground and vascular. The secretory tissue system is not considered a basic system; it is a specialised type often derived from other tissues. Secretory structures include glands, resin ducts and latex cells, but they are not part of the primary classification. The basic systems are defined by their universal presence and primary functions.

Q37. Xylem and phloem together constitute:

Correct Answer: (c)
Xylem and phloem together form vascular bundles. These bundles are the units of the vascular system. They may be arranged in different patterns (e.g., ring in dicot stems, scattered in monocot stems). Medullary rays are parenchymatous connections between bundles; stele includes all tissues inside endodermis; ground tissue is everything else.

Q38. In the shoot system, trichomes are usually:

Correct Answer: (b)
Trichomes in the shoot are typically multicellular, though some may be unicellular. They are living at maturity in many cases. They vary in form and function; some are glandular and secrete substances. They are not lignified (unlike sclerenchyma) and are not dead at maturity (unlike some fibers). The multicellular nature allows for diverse shapes and functions.

Q39. Vascular bundles in dicot leaves occur in:

Correct Answer: (c)
Vascular bundles in dicot leaves are present in both the midrib (main vein) and the lateral veins. They form a network of veins (reticulate venation) that supply water and nutrients to the leaf and export photosynthates. The petiole also contains vascular bundles, but the question asks specifically about the leaf blade.

Q40. Vascular bundles of monocot stems are called closed because:

Correct Answer: (c)
Monocot vascular bundles lack cambium, so they cannot produce secondary xylem and phloem. Hence they are termed 'closed'. They are also often scattered in the ground tissue and surrounded by a sclerenchymatous bundle sheath. The absence of cambium means no secondary growth, so monocot stems do not increase in girth significantly.

Q41. Epidermal hairs on the stem are called:

Correct Answer: (b)
Epidermal hairs on the stem are termed trichomes. They may be unicellular or multicellular, branched or unbranched. Trichomes can be glandular (secretory) or non-glandular. They serve various functions like reducing transpiration, reflecting light, and providing protection against herbivores. They are distinct from root hairs which are unicellular and occur on roots.

Q42. Cuticle is generally absent in:

Correct Answer: (c)
Cuticle is absent in roots because roots are involved in absorption of water and minerals from the soil. A waxy layer would hinder this function. In aerial parts like leaves and stems, cuticle is present to minimise water loss. The absence of cuticle in roots also facilitates the movement of water into the root cortex through apoplast.

Q43. Epidermal tissue system comprises epidermal cells, stomata and:

Correct Answer: (b)
The epidermal tissue system includes the epidermal cells, stomata (pores for gas exchange) and epidermal appendages like trichomes and root hairs. Trichomes are hair-like outgrowths that can be unicellular or multicellular. These structures help in protection, secretion and reduction of water loss. They are absent in roots where root hairs are unicellular extensions.

Q44. Match the tissue system with its main components:

Column-I (Tissue System)	Column-II (Components)
A. Epidermal tissue system	(I) Epidermal cells, stomata, trichomes
B. Ground tissue system	(II) Cortex, pericycle, pith
C. Vascular tissue system	(III) Xylem, phloem

Correct Answer: (a)
The epidermal tissue system consists of epidermis, stomata and trichomes (I). The ground tissue system includes cortex, pericycle and pith (II). The vascular system is made of xylem and phloem (III). Thus, the correct matching is A-I, B-II, C-III.

Q45. Assertion: In dicot leaves, palisade parenchyma is located on the adaxial side. Reason: Palisade cells receive more light and are important for photosynthesis.

Correct Answer: (a)
Both statements are true. Palisade parenchyma is situated on the adaxial (upper) side of dicot leaves, which receives more sunlight. The reason correctly explains this positioning because these cells contain abundant chloroplasts and are the primary photosynthetic tissue. Their location maximises light absorption, so the reason is a valid explanation.

Q46. According to the summary, plant tissues are broadly classified into:

Correct Answer: (a)
Plant tissues are broadly classified into meristematic (dividing) and permanent (non-dividing, differentiated). Simple and complex tissues are subtypes of permanent tissues. Dermal and vascular are tissue systems, not the primary classification. Primary and secondary xylem are types of vascular tissue.

Q47. Root hairs primarily help in:

Correct Answer: (c)
Root hairs are specialised for absorption of water and dissolved minerals from the soil. Their thin walls and large surface area maximise contact with soil particles. They also help in anchoring the plant. They do not photosynthesise (lack chloroplasts) and do not provide significant mechanical support.

Q48. Assertion: Cuticle is absent in roots. Reason: Cuticle prevents excessive absorption of water in roots.

Correct Answer: (c)
The assertion is true: cuticle is generally absent in roots to allow water absorption. The reason is false: cuticle does not prevent absorption; it prevents water loss (transpiration). In roots, absence of cuticle facilitates the uptake of water and minerals from the soil. Therefore, the assertion is correct but the reason is incorrect.

Q49. Conjoint vascular bundles are commonly found in:

Correct Answer: (b)
Conjoint vascular bundles are typical of stems and leaves. In roots, the vascular bundles are radial. In stems, they are arranged in a ring (dicots) or scattered (monocots). In leaves, they form the veins. Conjoint bundles allow efficient transport of water and food in the same vascular strand.

Q50. When bulliform cells become flaccid due to water stress, leaves:

Correct Answer: (c)
When bulliform cells lose turgor (become flaccid) due to water deficiency, the leaf surface curls inward, reducing the exposed area and thus minimising transpirational water loss. This is a protective mechanism in grasses. When water is available, they regain turgor and the leaf unrolls.

Q51. How many main tissue systems are recognised on the basis of structure and location in the plant body?

Correct Answer: (b)
Based on structure and location, plant tissues are grouped into three main systems: epidermal, ground (fundamental) and vascular (conducting). The epidermal system forms the outer covering, the ground system fills the bulk, and the vascular system conducts water and food. This classification is fundamental to understanding plant anatomy.

Q52. Epidermal cells are generally:

Correct Answer: (c)
Epidermal cells are parenchymatous, meaning they are thin-walled, living and have a large central vacuole. They contain a small amount of cytoplasm and are usually devoid of chloroplasts (except guard cells). Their large vacuole helps in storage and maintaining turgor. The cell walls are often cutinised on the outer surface.

Q53. In dicot stem, pericycle occurs:

Correct Answer: (b)
In dicot stems, the pericycle is present on the inner side of the endodermis and above the phloem (i.e., it surrounds the vascular bundles). It is often multilayered and parenchymatous, sometimes sclerenchymatous. It is part of the stele. It may give rise to lateral meristems during secondary growth.

Q54. Assertion: The endodermis of dicot stems is also called starch sheath. Reason: Its cells are rich in starch grains.

Correct Answer: (a)
Both assertion and reason are true. In dicot stems, the endodermis often stores starch, hence it is called the starch sheath. The abundance of starch grains is the reason for this name. Thus, the reason correctly explains the assertion.

Q55. Assertion: Spongy parenchyma of dicot leaves has numerous air spaces. Reason: These air spaces facilitate gaseous exchange within the leaf.

Correct Answer: (a)
Both assertion and reason are true. Spongy parenchyma is loosely arranged with large intercellular spaces (air cavities) that allow CO₂ and O₂ to diffuse easily. This facilitates gaseous exchange during photosynthesis and respiration. The reason correctly explains the structural adaptation.

Q56. Match the tissue/structure with its location:

Column-I	Column-II
A. Bulliform cells	(I) Adaxial epidermis of grass leaves
B. Casparian strips	(II) Endodermis of roots
C. Starch sheath	(III) Endodermis of dicot stem
D. Conjunctive tissue	(IV) Between xylem and phloem in dicot root

Correct Answer: (a)
Bulliform cells occur in adaxial epidermis of grass leaves (I). Casparian strips are in the endodermis of roots (II). Starch sheath is the endodermis of dicot stem (III). Conjunctive tissue lies between xylem and phloem in dicot root (IV). The correct matching is A-I, B-II, C-III, D-IV.

Q57. Bulliform cells are:

Correct Answer: (b)
Bulliform cells are large, empty, colourless cells found in the adaxial (upper) epidermis of grass leaves. They are involved in leaf rolling during water stress to reduce transpiration. When turgid, they keep the leaf flat; when flaccid, they cause the leaf to curl inward. They are not guard cells or root cells.

Q58. Ring arrangement of vascular bundles is a characteristic feature of:

Correct Answer: (b)
In dicot stems, vascular bundles are arranged in a ring (eustele). This allows for secondary growth via cambium present between xylem and phloem. In monocot stems, bundles are scattered (atactostele). In roots, bundles are radial. The ring arrangement is a diagnostic feature of dicot stems.

Q59. Mesophyll of a dicot leaf is composed of:

Correct Answer: (a)
In dicot leaves, the mesophyll is differentiated into two distinct layers: palisade parenchyma (upper, elongated cells) and spongy parenchyma (lower, irregular cells with air spaces). This differentiation enhances light absorption and gas exchange. Monocot leaves usually have undifferentiated mesophyll.

Q60. The parallel venation of monocot leaves is reflected anatomically by:

Correct Answer: (b)
In monocot leaves with parallel venation, the vascular bundles are of approximately similar size (except the main midrib bundle), and they run parallel to each other. This is visible in transverse sections. The bundles are usually surrounded by a bundle sheath. This uniform size reflects the parallel arrangement.

Q61. Which one of the following plant tissue types is correctly matched with a function mentioned in the chapter?

Correct Answer: (b)
Ground tissue is correctly matched with mechanical support and storage. Meristematic tissue is for growth, not food translocation (that is phloem). Epidermal tissue is protective, not for secondary growth (cambium does that). Vascular tissue conducts water and food, not photosynthesis. So ground tissue is the correct match.

Q62. Which feature best distinguishes monocot and dicot stems anatomically as per the chapter?

Correct Answer: (b)
The presence of cambium (open bundles) vs its absence (closed bundles) and the arrangement of bundles (ring vs scattered) are the key distinguishing features between monocot and dicot stems. Stomata, epidermis and pith are not diagnostic on their own.

Q63. Secondary growth commonly occurs in:

Correct Answer: (b)
Secondary growth (increase in girth) is a feature of most dicot roots and stems due to the presence of lateral meristems (cambium). Monocots generally lack cambium and do not undergo secondary growth. Leaves do not exhibit secondary growth. Thus, the correct answer is dicot roots and stems.

Q64. In dicot roots, parenchymatous cells between xylem and phloem are called:

Correct Answer: (b)
In dicot roots, the parenchymatous cells lying between the xylem and phloem bundles are termed conjunctive tissue. It is a type of ground tissue within the stele. Medullary rays are similar but occur in stems. Conjunctive tissue may become cambial during secondary growth. It fills the spaces between vascular bundles.

Q65. Stomatal aperture, guard cells and surrounding subsidiary cells together form the:

Correct Answer: (b)
The stomatal apparatus comprises the stomatal pore (aperture), the two guard cells and the surrounding subsidiary cells. This entire structure works together to regulate gas exchange and transpiration. The subsidiary cells may be absent in some plants, but when present they are included in the definition. The term 'stomatal complex' is also used synonymously, but the standard term in this context is stomatal apparatus.

Q66. In dicot stem, the hypodermis is mainly formed of:

Correct Answer: (b)
The hypodermis in dicot stems consists of a few layers of collenchyma, which is a living tissue with thickened cell walls at the corners. Collenchyma provides flexible mechanical support to the young stem. It is usually just below the epidermis. In monocot stems, the hypodermis is often sclerenchymatous.

Q67. When xylem and phloem in a vascular bundle are arranged in an alternate manner along different radii, the arrangement is:

Correct Answer: (d)
Radial arrangement occurs when xylem and phloem are on different radii, alternating with each other. This is characteristic of roots. In radial bundles, the xylem and phloem are separate patches arranged in a circle. In conjoint bundles, they are on the same radius. Collateral and bicollateral are types of conjoint bundles.

Q68. In dicot stems, the presence of cambium between xylem and phloem makes the vascular bundles:

Correct Answer: (b)
The presence of cambium (a lateral meristem) between xylem and phloem makes the vascular bundle 'open' because it can undergo secondary growth. This allows the stem to increase in girth. In contrast, bundles without cambium are 'closed' and do not show secondary growth. Dicot stems typically have open bundles arranged in a ring.

Q69. Compared to dicot roots, monocot roots typically have:

Correct Answer: (b)
Monocot roots usually have more than six xylem bundles (polyarch), whereas dicot roots have fewer (diarch to hexarch). This is a distinguishing anatomical feature. Monocot roots also have a large pith and undergo no secondary growth. The number of xylem bundles is correlated with the root's diameter.

Q70. Regarding epidermal tissue system, which statements are correct?
(i) It forms the outermost covering of the whole plant body.
(ii) It includes stomata and trichomes.
(iii) It forms the main bulk of the plant body.

Correct Answer: (a)
The epidermal tissue system is the outermost covering (i) and includes stomata and trichomes (ii). However, it does not form the main bulk of the plant; that is the ground tissue system (iii is false). Therefore, only (i) and (ii) are correct.

Q71. Many cells of epiblema in roots protrude as:

Correct Answer: (b)
Many epiblema cells extend outwards to form unicellular root hairs. These hairs increase the surface area for water and mineral absorption. They are short-lived and are replaced as the root grows. They are not lateral roots (which are endogenous), nor trichomes (which are shoot epidermal hairs), nor bulliform cells (found in grass leaves).

Q72. Which cells associated with stomata may become specialised in shape and size and are called subsidiary cells?

Correct Answer: (b)
Subsidiary cells are specialised epidermal cells that surround the guard cells. They differ from ordinary epidermal cells in shape, size and arrangement. They often assist in the functioning of the stoma, though their exact role varies. They are not trichomes, pericycle or mesophyll cells.

Q73. Assertion: In dicot stems, vascular bundles are open. Reason: They contain a cambium between xylem and phloem that can form secondary tissues.

Correct Answer: (a)
Both statements are true. Dicot stems have open vascular bundles because they possess cambium, a lateral meristem that produces secondary xylem and phloem, leading to increase in girth. The reason correctly explains why they are called 'open'.

Q74. The inner walls of guard cells (towards the stomatal pore) are:

Correct Answer: (b)
The inner walls of guard cells (adjacent to the stomatal pore) are highly thickened and less elastic. The outer walls are thin and elastic. When guard cells become turgid, the thin outer walls stretch, causing the inner thick walls to bulge outward and open the pore. This differential thickening is key to stomatal movement.

Q75. The outermost layer of a dicot root is called:

Correct Answer: (b)
In roots, the outermost layer is called epiblema (or rhizodermis). It is a special epidermal layer that lacks cuticle and often bears root hairs. In older roots, the epiblema may be replaced by periderm (cork). The term 'epidermis' is sometimes used, but 'epiblema' is more specific to roots. It functions in absorption.

Q76. Regarding ground tissue in stems and roots, which statements are correct?
(i) It consists mainly of parenchyma, collenchyma and sclerenchyma.
(ii) Cortex, pericycle, pith and medullary rays are parts of ground tissue.
(iii) It is completely absent in leaves.

Correct Answer: (a)
Ground tissue is made of parenchyma, collenchyma and sclerenchyma (i). It includes cortex, pericycle, pith and medullary rays (ii). However, it is not absent in leaves; in leaves it is called mesophyll (iii is false). Hence (i) and (ii) are correct.

Q77. Regarding dicot roots, which statements are correct?
(i) Epiblema is the outermost layer.
(ii) Endodermis has Casparian strips.
(iii) Pith is large and well developed.

Correct Answer: (a)
In dicot roots, epiblema is the outermost layer (i) and endodermis has Casparian strips (ii). However, pith is small or inconspicuous in dicot roots, not large (iii is false). Thus only (i) and (ii) are correct.

Q78. In monocot stem, vascular bundles are:

Correct Answer: (b)
Monocot stems have vascular bundles scattered throughout the ground tissue (atactostele). They are not arranged in a distinct ring. This scattered arrangement is a key feature distinguishing monocot from dicot stems. Each bundle is closed (no cambium) and often surrounded by a sclerenchymatous sheath.

Q79. In monocot stem, the hypodermis is mainly:

Correct Answer: (c)
The hypodermis in monocot stems is sclerenchymatous, consisting of thick-walled lignified cells that provide mechanical strength. This is in contrast to dicot stems where hypodermis is collenchymatous. The sclerenchymatous hypodermis is a characteristic feature of monocot stems, often seen in maize.

Q80. In conjoint vascular bundles, xylem and phloem are:

Correct Answer: (b)
In conjoint bundles, xylem and phloem lie on the same radius, i.e., they are together. This is the common arrangement in stems and leaves. The xylem is usually towards the centre (endarch in stems) and phloem towards the outside. This type is further classified as collateral or bicollateral based on the position of phloem.

Q81. Match the organ with a key anatomical feature:

Column-I (Organ)	Column-II (Anatomical Feature)
A. Monocot root	(I) Polyarch xylem, large pith
B. Dicot root	(II) Small or inconspicuous pith
C. Monocot stem	(III) Scattered closed vascular bundles
D. Dicot stem	(IV) Ring of open vascular bundles

Correct Answer: (a)
Monocot roots have polyarch xylem and large pith (I). Dicot roots have small or inconspicuous pith (II). Monocot stems have scattered closed vascular bundles (III). Dicot stems have a ring of open vascular bundles (IV). The correct matching is A-I, B-II, C-III, D-IV.

Q82. Each stoma is bordered by:

Correct Answer: (a)
Each stoma is composed of two guard cells that are bean-shaped in dicots and dumb-bell shaped in monocots. The guard cells regulate the size of the stomatal pore by changing their turgor. They are chloroplast-containing and can perform photosynthesis. The surrounding epidermal cells may become specialised as subsidiary cells, but the basic unit is the two guard cells.

Q83. The vascular tissue system is formed by:

Correct Answer: (b)
The vascular tissue system consists of complex tissues: xylem (for water and mineral conduction) and phloem (for food conduction). These tissues are arranged in vascular bundles. They are distributed throughout the plant and are responsible for long-distance transport. The vascular system also provides mechanical support.

Q84. The layer just inside the endodermis in roots, consisting of a few layers of thick-walled cells, is called:

Correct Answer: (a)
The pericycle is the layer immediately inside the endodermis. It is typically made of thick-walled parenchyma cells. It is a meristematic layer that gives rise to lateral roots and vascular cambium during secondary growth. In some roots, the pericycle may be sclerenchymatous. It is part of the stele.

Q85. In most conjoint vascular bundles of stems and leaves, phloem is usually located:

Correct Answer: (b)
In typical conjoint bundles (collateral), phloem is located only on the outer side of xylem. This is the standard arrangement in stems and leaves. In bicollateral bundles, phloem is present on both outer and inner sides of xylem (e.g., in Cucurbitaceae). The phloem transports organic nutrients from leaves to other parts.

Q86. Regarding monocot stems, which statements are correct?
(i) Vascular bundles are scattered in the ground tissue.
(ii) Each bundle is surrounded by a sclerenchymatous bundle sheath.
(iii) Phloem parenchyma is absent.

Correct Answer: (d)
All three statements are correct for monocot stems: bundles are scattered (i), each has a sclerenchymatous sheath (ii), and phloem parenchyma is absent (iii). These are characteristic features of monocot stem anatomy.

Q87. All tissues inner to endodermis such as pericycle, vascular bundles and pith together constitute the:

Correct Answer: (a)
The stele includes all tissues inside the endodermis: pericycle, vascular bundles (xylem and phloem), conjunctive tissue and pith (if present). It is the central cylinder of the root or stem. The cortex and epidermis are outside the endodermis. The stele is the conducting and supporting core.

Q88. In grasses, guard cells are characteristically:

Correct Answer: (b)
In grasses (monocots), guard cells are dumb-bell shaped, with narrow middle portions and bulbous ends. This shape allows rapid changes in pore size with minimal turgor changes. The inner walls are thick, and the outer walls are thin, facilitating movement. This contrasts with the bean-shaped guard cells typical of dicots.

Q89. Assertion: Epidermis in primary plant body is usually single-layered. Reason: Epidermal cells are compactly arranged to form a continuous layer.

Correct Answer: (b)
The assertion that epidermis is usually single-layered is true. The reason that epidermal cells are compactly arranged to form a continuous layer is also true. However, the compact arrangement explains why the epidermis is continuous, not why it is single-layered. The single-layered nature is a separate characteristic; the reason does not specifically explain that aspect, so it is not the correct explanation for the assertion.

Q90. The waxy thick layer covering the outer side of epidermis is called:

Correct Answer: (b)
The cuticle is a waxy, waterproof layer secreted by epidermal cells on their outer surface. It reduces water loss through transpiration. It also provides protection against mechanical damage and microbial attack. The cuticle is thicker in xerophytes and absent in roots to allow water absorption. It is composed of cutin, a fatty substance.

Q91. The cortex of dicot root consists of several layers of:

Correct Answer: (b)
The cortex in dicot roots is composed of thin-walled parenchyma cells with conspicuous intercellular spaces. These cells store food and allow passage of water and minerals. They are not collenchymatous (which have thick corners) or sclerenchymatous (lignified). The cortex is a ground tissue region between epiblema and endodermis.

Q92. In isobilateral leaves, mesophyll is:

Correct Answer: (b)
In monocot leaves (isobilateral), the mesophyll is not differentiated into palisade and spongy parenchyma. Instead, it consists of compact, uniform parenchyma cells with chloroplasts. This is a structural adaptation related to the parallel venation and erect habit of many monocots.

Q93. Assertion: Trichomes on stems may be secretory. Reason: Trichomes only provide mechanical strength and are always non-secretory.

Correct Answer: (c)
Trichomes can be glandular and secrete substances such as oils, resins or nectar, so the assertion is true. The reason states that trichomes are always non-secretory, which is false. Some trichomes are indeed secretory (e.g., in mint, basil). Therefore, the reason is incorrect.

Q94. Walls of endodermal cells in roots show deposition of suberin in the form of:

Correct Answer: (b)
Endodermal cells have Casparian strips on their radial and tangential walls, consisting of suberin and lignin. These strips are impermeable to water, forcing water to pass through the protoplast (symplast) rather than through cell walls (apoplast). This ensures selective uptake of minerals. Casparian strips are a key feature of root endodermis.

Q95. The tissue between upper and lower epidermis of a leaf is called:

Correct Answer: (b)
The mesophyll is the ground tissue of leaves, located between the upper and lower epidermis. It is photosynthetic and contains chloroplasts. In dicots, it is differentiated into palisade and spongy parenchyma. In monocots, it is often undifferentiated. Cortex and pith are found in stems and roots, not leaves.

Q96. The innermost layer of cortex in dicot stem, rich in starch grains, is called:

Correct Answer: (b)
In dicot stems, the innermost layer of the cortex is the endodermis, which often contains abundant starch grains and is therefore called the starch sheath. It functions as a storage layer and may also regulate transport. This is distinct from the root endodermis which has Casparian strips. The starch sheath is a characteristic of many dicot stems.

Q97. The primary function of stomata is to regulate:

Correct Answer: (b)
Stomata regulate transpiration (loss of water vapour) and gaseous exchange (uptake of CO₂ for photosynthesis and release of O₂). The opening and closing of stomata are controlled by guard cells in response to environmental conditions. This regulation is crucial for maintaining water balance and photosynthetic efficiency. Stomata do not directly absorb minerals or provide support.

Q98. Water-containing cavities in monocot stem are located:

Correct Answer: (b)
In monocot stems, water-containing cavities (lysigenous cavities) are often present within the vascular bundles, particularly in the xylem region. These cavities store water and are formed by the breakdown of cells. They are not in cortex or pith. This is a feature of many monocot stems, e.g., in maize.

Q99. Mesophyll cells mainly perform:

Correct Answer: (c)
Mesophyll cells contain abundant chloroplasts and are the primary site of photosynthesis in leaves. They convert light energy into chemical energy. They are not involved in water transport (xylem) or mechanical support (though they may provide some). Reproduction is not a function of mesophyll.

Q100. Palisade parenchyma cells in a dicot leaf are:

Correct Answer: (b)
Palisade parenchyma cells are elongated and arranged perpendicular to the leaf surface, forming a compact layer just below the upper epidermis. They contain many chloroplasts and are adapted for light absorption. They are not round or loosely arranged; that describes spongy parenchyma. They are living parenchyma, not sclerenchyma.