Chapter 5: Morphology 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): In monocotyledonous plants, the primary root is short-lived and is replaced by roots arising from the base of the stem. Reason (R): These stem-based roots constitute the fibrous root system, as seen in wheat.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): The root cap protects the tender apex of the root as it makes its way through the soil. Reason (R): The root cap is located in the region of maturation and contains actively dividing meristematic cells.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): Root hairs are present in the region of elongation of the root. Reason (R): Root hairs absorb water and minerals from the soil and are thread-like extensions of epidermal cells.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): The stem is the ascending part of the axis that develops from the plumule of the embryo. Reason (R): The stem bears nodes and internodes, and leaves are borne at nodes.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 5

Logic Check

Assertion (A): In dicotyledonous plants, the leaves generally possess reticulate venation. Reason (R): Reticulate venation means the veinlets form a network within the lamina and is characteristic of dicots.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 6

Logic Check

Assertion (A): In a compound leaf, a bud is present in the axil of each individual leaflet. Reason (R): The presence of axillary buds distinguishes leaflets of compound leaves from simple leaves.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 7

Logic Check

Assertion (A): In Alstonia, more than two leaves arise at each node forming a whorl. Reason (R): This type of phyllotaxy is called whorled phyllotaxy.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 8

Logic Check

Assertion (A): In racemose inflorescence, the main axis terminates in a flower and growth is limited. Reason (R): Flowers in racemose inflorescence are borne in acropetal succession.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 9

Logic Check

Assertion (A): When a flower can be divided into two equal halves only in one particular vertical plane, it is zygomorphic. Reason (R): Pea and bean flowers are examples of zygomorphic flowers.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 10

Logic Check

Assertion (A): In valvate aestivation, the margins of sepals or petals overlap each other in a consistent direction. Reason (R): Valvate aestivation is seen in Calotropis where petals just touch at the margins without overlapping.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): China rose shows twisted aestivation where one margin of each petal overlaps the next in a consistent direction. Reason (R): Twisted aestivation is a characteristic of family Malvaceae and is also seen in lady's finger and cotton.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): In pea flowers, the vexillary aestivation involves five petals where the largest overlaps two lateral petals, which in turn overlap the two smallest anterior petals. Reason (R): Vexillary aestivation is also called papilionaceous and is characteristic of family Fabaceae (Papilionoideae).

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 13

Logic Check

Assertion (A): When stamens are attached to the petals they are called epiphyllous. Reason (R): Epipetalous stamens are those attached to petals, as seen in brinjal.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): In monoadelphous stamens, all the filaments are united into a single bundle while the anthers remain free. Reason (R): Monoadelphous condition is seen in china rose where the staminal column surrounds the style.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 15

Logic Check

Assertion (A): When carpels are fused together, the gynoecium is called apocarpous. Reason (R): Syncarpous gynoecium is seen in mustard and tomato where carpels are fused.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 16

Logic Check

Assertion (A): In hypogynous flowers, the gynoecium occupies the highest position on the thalamus and the ovary is superior. Reason (R): Mustard, china rose, and brinjal are examples of hypogynous flowers.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 17

Logic Check

Assertion (A): In epigynous flowers such as guava, the ovary is said to be inferior. Reason (R): In epigynous flowers, the margin of the thalamus grows upward, encloses the ovary completely, and gets fused with it.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 18

Logic Check

Assertion (A): In marginal placentation, the ovules are borne on the central axis in a multilocular ovary. Reason (R): Marginal placentation is seen in pea where the placenta forms a ridge along the ventral suture.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 19

Logic Check

Assertion (A): In basal placentation, a single ovule is attached to the placenta at the base of the ovary. Reason (R): Basal placentation is characteristic of sunflower and marigold, resulting in one-seeded fruits.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 20

Logic Check

Assertion (A): A fruit is defined as a mature ovary developed after fertilisation. Reason (R): A parthenocarpic fruit is also formed after fertilisation of the ovary.

Reasoning Options

ByteNotes

Chapter sections

Chapter 5: Morphology of Flowering Plants | Assertion-Reason

Assertion (A): In monocotyledonous plants, the primary root is short-lived and is replaced by roots arising from the base of the stem. Reason (R): These stem-based roots constitute the fibrous root system, as seen in wheat.

Assertion (A): The root cap protects the tender apex of the root as it makes its way through the soil. Reason (R): The root cap is located in the region of maturation and contains actively dividing meristematic cells.

Assertion (A): Root hairs are present in the region of elongation of the root. Reason (R): Root hairs absorb water and minerals from the soil and are thread-like extensions of epidermal cells.

Assertion (A): The stem is the ascending part of the axis that develops from the plumule of the embryo. Reason (R): The stem bears nodes and internodes, and leaves are borne at nodes.

Assertion (A): In dicotyledonous plants, the leaves generally possess reticulate venation. Reason (R): Reticulate venation means the veinlets form a network within the lamina and is characteristic of dicots.

Assertion (A): In a compound leaf, a bud is present in the axil of each individual leaflet. Reason (R): The presence of axillary buds distinguishes leaflets of compound leaves from simple leaves.

Assertion (A): In Alstonia, more than two leaves arise at each node forming a whorl. Reason (R): This type of phyllotaxy is called whorled phyllotaxy.

Assertion (A): In racemose inflorescence, the main axis terminates in a flower and growth is limited. Reason (R): Flowers in racemose inflorescence are borne in acropetal succession.

Assertion (A): When a flower can be divided into two equal halves only in one particular vertical plane, it is zygomorphic. Reason (R): Pea and bean flowers are examples of zygomorphic flowers.

Assertion (A): In valvate aestivation, the margins of sepals or petals overlap each other in a consistent direction. Reason (R): Valvate aestivation is seen in Calotropis where petals just touch at the margins without overlapping.

Assertion (A): China rose shows twisted aestivation where one margin of each petal overlaps the next in a consistent direction. Reason (R): Twisted aestivation is a characteristic of family Malvaceae and is also seen in lady's finger and cotton.

Assertion (A): When stamens are attached to the petals they are called epiphyllous. Reason (R): Epipetalous stamens are those attached to petals, as seen in brinjal.

Assertion (A): In monoadelphous stamens, all the filaments are united into a single bundle while the anthers remain free. Reason (R): Monoadelphous condition is seen in china rose where the staminal column surrounds the style.

Assertion (A): When carpels are fused together, the gynoecium is called apocarpous. Reason (R): Syncarpous gynoecium is seen in mustard and tomato where carpels are fused.

Assertion (A): In hypogynous flowers, the gynoecium occupies the highest position on the thalamus and the ovary is superior. Reason (R): Mustard, china rose, and brinjal are examples of hypogynous flowers.

Assertion (A): In epigynous flowers such as guava, the ovary is said to be inferior. Reason (R): In epigynous flowers, the margin of the thalamus grows upward, encloses the ovary completely, and gets fused with it.

Assertion (A): In marginal placentation, the ovules are borne on the central axis in a multilocular ovary. Reason (R): Marginal placentation is seen in pea where the placenta forms a ridge along the ventral suture.

Assertion (A): In basal placentation, a single ovule is attached to the placenta at the base of the ovary. Reason (R): Basal placentation is characteristic of sunflower and marigold, resulting in one-seeded fruits.

Assertion (A): A fruit is defined as a mature ovary developed after fertilisation. Reason (R): A parthenocarpic fruit is also formed after fertilisation of the ovary.

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