Statement I: The stem develops from the radicle of the germinating seed. Statement II: The region of the stem where leaves are borne is called the internode, while the portion between two nodes is called the node. Select the correct option:
Both statements are incorrect. The stem develops from the plumule of the embryo of a germinating seed, not the radicle. Leaves are borne at nodes, and the portion between two nodes is called the internode.
Question 112 of 300
📘 CLASS XI
Assertion (A): Stems are always the primary organs of photosynthesis in all adult higher plants. Reason (R): The primary function of any stem is always to conduct water, minerals, and photosynthates.
Assertion is false because leaves are the primary vegetative organs for photosynthesis in most higher plants, though some modified stems can photosynthesize. Reason is true because conduction of water, minerals, and photosynthates is indeed the main or primary function of a stem.
Question 113 of 300
📘 CLASS XI
Statement I: Stems can undergo modifications to perform specialized functions such as food storage, support, protection, and vegetative propagation. Statement II: Underground stems like potato are modified for respiration because they lack green chlorophyll. Select the correct option:
Statement I is correct; stems modify for storage, support, protection, and propagation. Statement II is incorrect because the underground stem of the potato is modified for food storage, not respiration.
Question 114 of 300
📘 CLASS XI
Assertion (A): Nodes are physiologically more active than internodes in terms of organogenesis. Reason (R): Leaves, branches, and flowers originate specifically at the nodal regions of the stem.
Organogenesis (formation of leaves, buds, and branches) occurs specifically at the nodes, making them centers of localized growth and differentiation compared to internodes, which primarily elongate.
Question 115 of 300
📘 CLASS XI
Statement I: Adventitious roots never arise from stem tissue. Statement II: Underground modified stems can be distinguished from roots by the presence of nodes and internodes. Select the correct option:
Statement I is incorrect because adventitious roots regularly arise from stem tissue, such as at the base of the stem (fibrous roots in monocots). Statement II is correct because the presence of nodes and internodes is a diagnostic feature of stem tissue, absent in roots.
Question 116 of 300
📘 CLASS XI
Assertion (A): The stem can be considered an ascending axis of the plant. Reason (R): It develops from the plumule and grows away from gravity towards light.
The stem is the ascending part of the plant axis, developing from the plumule of the embryo and displaying positive phototropism, growing upwards into the light.
Question 117 of 300
📘 CLASS XI
Assertion (A): In monocotyledons, the leaf base provides mechanical protection to the young stem. Reason (R): In monocots, the leaf base expands into a sheath covering the stem partially or wholly.
In monocotyledons, the leaf base expands into a protective sheath that covers the stem either partially or completely, acting as physical shielding for the node and young stem tissues.
Question 118 of 300
📘 CLASS XI
Statement I: The pulvinus is a swollen leaf base characteristic of many leguminous plants. Statement II: The pulvinus helps hold the leaf blade to light and enables it to flutter in the wind to cool the lamina. Select the correct option:
Statement I is correct; in some leguminous plants, the leaf base becomes swollen, known as the pulvinus. Statement II is incorrect because it is the long, thin, flexible petiole (not the pulvinus) that helps hold the blade to light, allows fluttering, cools the leaf, and brings fresh air to the leaf surface.
Question 119 of 300
📘 CLASS XI
Examine the following statements regarding leaf venation: Statement I: Reticulate venation is characterized by veinlets forming a network in the lamina. Statement II: Parallel venation is the characteristic feature of most dicotyledonous plants. Select the correct option:
Statement I is correct; when veinlets form a network, it is called reticulate venation. Statement II is incorrect because parallel venation is characteristic of most monocotyledons, whereas dicotyledonous plants generally possess reticulate venation.
Question 120 of 300
📘 CLASS XI
Assertion (A): In simple leaves, the lamina is always entirely smooth and never shows any incisions. Reason (R): If incisions in a simple leaf occur, they must touch the midrib to divide it into multiple leaflets.
Both statements are false. A simple leaf's lamina can be entire OR incised, provided the incisions do not reach or touch the midrib. If the incisions touch the midrib and break the lamina into separate leaflets, it is classified as a compound leaf, not simple.
