Chapter 6: Anatomy of Flowering Plants Assertion-Reason Questions | biology Class 11 CBSE

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 1

Logic Check

Assertion (A): The cuticle is present on the epidermis of leaves and stems but absent in roots. Reason (R): Roots need to absorb water from the soil, and a cuticle would prevent this absorption by creating a waterproof barrier.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 2

Logic Check

Assertion (A): Stomata are present in the epidermis of leaves and regulate transpiration and gaseous exchange. Reason (R): Guard cells possess chloroplasts and have differentially thickened walls that enable them to open and close the stomatal pore.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 3

Logic Check

Assertion (A): Root hairs are multicellular structures that help in the absorption of water and minerals. Reason (R): Root hairs are unicellular elongations of epidermal cells that increase the surface area for absorption.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): Trichomes on the shoot system help in preventing water loss due to transpiration. Reason (R): Trichomes are multicellular epidermal hairs that trap a layer of humid air near the plant surface, reducing the vapour pressure gradient driving transpiration.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 5

Logic Check

Assertion (A): Vascular bundles in monocotyledonous stems are called closed. Reason (R): Closed vascular bundles lack cambium between the xylem and phloem, so they cannot form secondary tissues.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 6

Logic Check

Assertion (A): Dicotyledonous stems have vascular bundles arranged in a ring. Reason (R): The ring arrangement of vascular bundles is the defining anatomical characteristic of the dicot stem and distinguishes it from the monocot stem.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 7

Logic Check

Assertion (A): The endodermis of a dicot root has Casparian strips, while the endodermis of a dicot stem does not. Reason (R): The dicot stem endodermis (starch sheath) functions as a storage layer, whereas the root endodermis functions as a selective barrier regulating mineral entry into the stele.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 8

Logic Check

Assertion (A): Monocotyledonous roots do not undergo secondary growth. Reason (R): Monocot roots are polyarch and lack sufficient conjunctive tissue between the many xylem and phloem bundles to form a functional cambium ring.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): In a dorsiventral leaf, the abaxial epidermis bears more stomata than the adaxial epidermis. Reason (R): The adaxial surface is exposed to more direct sunlight and higher temperatures, where having fewer stomata reduces excessive transpirational water loss.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 10

Logic Check

Assertion (A): Bulliform cells cause the leaf to roll inward when they are turgid. Reason (R): When bulliform cells become flaccid due to water stress, they cause the leaf to curl inward, reducing transpirational water loss.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): Vascular bundles in roots are radial, while those in stems are conjoint. Reason (R): Radial bundles suit the multi-directional radial water inflow function of roots, while conjoint bundles suit the bidirectional axial transport function of stems.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): The pericycle in a dicot root initiates lateral roots. Reason (R): The pericycle is located outside the endodermis and consists of epidermal cells that can divide to form lateral roots.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): The mesophyll of an isobilateral (monocot) leaf is differentiated into palisade and spongy parenchyma. Reason (R): In an isobilateral leaf, both surfaces of the leaf are structurally similar and stomata are present on both surfaces.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): The hypodermis of a monocot stem is sclerenchymatous, while that of a dicot stem is collenchymatous. Reason (R): Monocot stems require rigid mechanical support from primary tissues alone since they cannot undergo secondary growth; dicot stems use flexible collenchyma to support young, still-elongating stems.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 15

Logic Check

Assertion (A): Conjoint open vascular bundles are found in dicot stems. Reason (R): Open vascular bundles possess cambium between xylem and phloem, which enables secondary growth in dicotyledonous plants.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): The pith in a dicot root is small or inconspicuous. Reason (R): In dicot roots, the few large xylem strands converge near the centre of the stele, leaving only a small amount of pith parenchyma at the centre.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 17

Logic Check

Assertion (A): Phloem parenchyma is absent in monocot stem vascular bundles. Reason (R): Water-containing cavities (protoxylem lacunae) are present in monocot stem vascular bundles.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 18

Logic Check

Assertion (A): Guard cells are the only epidermal cells that contain chloroplasts. Reason (R): Chloroplasts in guard cells produce ATP that powers the ion pumps responsible for K+ uptake, which drives the osmotic water entry needed for stomatal opening.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 19

Logic Check

Assertion (A): The cortex in a dicot root consists of several layers of thin-walled parenchymatous cells with intercellular spaces. Reason (R): The intercellular spaces in the root cortex facilitate the apoplastic (cell-wall-based) movement of water radially toward the stele.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 20

Logic Check

Assertion (A): The vascular bundles in conjoint type are common in stems and leaves. Reason (R): In conjoint vascular bundles, the phloem is located on the inner side of the xylem.

Reasoning Options

ByteNotes

Chapter sections

Chapter 6: Anatomy of Flowering Plants | Assertion-Reason

Assertion (A): The cuticle is present on the epidermis of leaves and stems but absent in roots. Reason (R): Roots need to absorb water from the soil, and a cuticle would prevent this absorption by creating a waterproof barrier.

Assertion (A): Stomata are present in the epidermis of leaves and regulate transpiration and gaseous exchange. Reason (R): Guard cells possess chloroplasts and have differentially thickened walls that enable them to open and close the stomatal pore.

Assertion (A): Root hairs are multicellular structures that help in the absorption of water and minerals. Reason (R): Root hairs are unicellular elongations of epidermal cells that increase the surface area for absorption.

Assertion (A): Trichomes on the shoot system help in preventing water loss due to transpiration. Reason (R): Trichomes are multicellular epidermal hairs that trap a layer of humid air near the plant surface, reducing the vapour pressure gradient driving transpiration.

Assertion (A): Vascular bundles in monocotyledonous stems are called closed. Reason (R): Closed vascular bundles lack cambium between the xylem and phloem, so they cannot form secondary tissues.

Assertion (A): Dicotyledonous stems have vascular bundles arranged in a ring. Reason (R): The ring arrangement of vascular bundles is the defining anatomical characteristic of the dicot stem and distinguishes it from the monocot stem.

Assertion (A): The endodermis of a dicot root has Casparian strips, while the endodermis of a dicot stem does not. Reason (R): The dicot stem endodermis (starch sheath) functions as a storage layer, whereas the root endodermis functions as a selective barrier regulating mineral entry into the stele.

Assertion (A): Monocotyledonous roots do not undergo secondary growth. Reason (R): Monocot roots are polyarch and lack sufficient conjunctive tissue between the many xylem and phloem bundles to form a functional cambium ring.

Assertion (A): In a dorsiventral leaf, the abaxial epidermis bears more stomata than the adaxial epidermis. Reason (R): The adaxial surface is exposed to more direct sunlight and higher temperatures, where having fewer stomata reduces excessive transpirational water loss.

Assertion (A): Bulliform cells cause the leaf to roll inward when they are turgid. Reason (R): When bulliform cells become flaccid due to water stress, they cause the leaf to curl inward, reducing transpirational water loss.

Assertion (A): Vascular bundles in roots are radial, while those in stems are conjoint. Reason (R): Radial bundles suit the multi-directional radial water inflow function of roots, while conjoint bundles suit the bidirectional axial transport function of stems.

Assertion (A): The pericycle in a dicot root initiates lateral roots. Reason (R): The pericycle is located outside the endodermis and consists of epidermal cells that can divide to form lateral roots.

Assertion (A): The mesophyll of an isobilateral (monocot) leaf is differentiated into palisade and spongy parenchyma. Reason (R): In an isobilateral leaf, both surfaces of the leaf are structurally similar and stomata are present on both surfaces.

Assertion (A): Conjoint open vascular bundles are found in dicot stems. Reason (R): Open vascular bundles possess cambium between xylem and phloem, which enables secondary growth in dicotyledonous plants.

Assertion (A): The pith in a dicot root is small or inconspicuous. Reason (R): In dicot roots, the few large xylem strands converge near the centre of the stele, leaving only a small amount of pith parenchyma at the centre.

Assertion (A): Phloem parenchyma is absent in monocot stem vascular bundles. Reason (R): Water-containing cavities (protoxylem lacunae) are present in monocot stem vascular bundles.

Assertion (A): Guard cells are the only epidermal cells that contain chloroplasts. Reason (R): Chloroplasts in guard cells produce ATP that powers the ion pumps responsible for K+ uptake, which drives the osmotic water entry needed for stomatal opening.

Assertion (A): The cortex in a dicot root consists of several layers of thin-walled parenchymatous cells with intercellular spaces. Reason (R): The intercellular spaces in the root cortex facilitate the apoplastic (cell-wall-based) movement of water radially toward the stele.

Assertion (A): The vascular bundles in conjoint type are common in stems and leaves. Reason (R): In conjoint vascular bundles, the phloem is located on the inner side of the xylem.

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