Test: Morphology of Flowering Plants - Assertion and Reasoning - NEET MCQ

The assertion is false because in hypogynous flowers, the gynoecium is not necessarily in the highest position. However, the reason is true because the ovary in hypogynous flowers is indeed superior.

Topic in NCERT: Position of floral parts on thalamus

Line in NCERT: "In the hypogynous flower the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior."

In vexillary type of aestivation, the posterior petal is the largest and covers almost the two lateral petals, and the latter in their turn, nearly overlap the two anterior or smallest petals. e.g, pea. This type of gestational is also called as descending imbricate aestivation.

Topic in NCERT: Aestivation

Line in NCERT: "In pea and bean flowers, there are five petals, the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary or papilionaceous."

In perigynous flowers , ovary is situated at the centre and other parts are on the rim of the thalamus hence, ovary is called half-inferior.

Topic in NCERT: Position of floral parts on thalamus

Line in NCERT: "The ovary here is said to be half inferior, e.g., plum, rose, peach."

The assertion is true as in monocotyledonous plants, the primary root is indeed short-lived and is replaced by a fibrous root system originating from the base of the stem. The reason is also true and correctly explains the assertion because the fibrous root system provides a more extensive network for efficient water and nutrient absorption from the soil.

Topic in NCERT: THE ROOT

Line in NCERT: "In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system, as seen in the wheat plant."

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
In imbricate aestivation one petal is completely inward, one petal is completely outward, one margin is internal and another margin is external.
Examples of ascending imbricate is Cassia and gulmohar not the reason.
So, the correct answer is B.
 

Topic in NCERT: Aestivation

Line in NCERT: "In Cassia and gulmohur, the aestivation is called imbricate."

Actinomorphic flowers are those flowers which can be divided into two equal halves along any plane of symmetry passing through the central axis. These flowers show radial symmetry, and not bilateral symmetry. For example, Datura, mustard and chilli.
Those flowers which can be divided into two equal halves (right and left) only along a single plane of symmetry passing through the central axis are known as zygomorphic flowers. For example, Cassia and gulmohur.
Hence, both assertion and reason statements are incorrect.
The correct option is C If both assertion and reason are false.

Topic in NCERT: THE FLOWER

Line in NCERT: "When a flower can be divided into two similar halves only in one particular vertical plane, it is zygomorphic."

The assertion is true as roots in some plants are indeed modified to perform additional functions beyond their primary roles of absorption and conduction. The reason accurately explains the assertion by listing examples of such modifications, including storage of food (e.g., in carrots), providing support (e.g., prop roots in banyan trees), and aiding in respiration (e.g., pneumatophores in mangroves).

Topic in NCERT: MODIFIED ROOTS IN PLANTS

Line in NCERT: "The roots in some plants get modified for storage of food, mechanical support and respiration."

The assertion is false because the ovary in hypogynous flowers is not positioned above the other floral parts in all cases. The reason is true because the calyx, corolla, and androecium are typically located below the ovary in hypogynous flowers.

Topic in NCERT: Position of floral parts on thalamus

Line in NCERT: "In the hypogynous flower the gynoecium occupies the highest position while the other parts are situated below it."

The assertion is correct for dicotyledonous plants, where the primary root develops into a long-lived tap root. The reason correctly explains the nature of the primary root in monocots.

Topic in NCERT: THE ROOT

Line in NCERT: "In majority of the dicotyledonous plants, the direct elongation of the radicle leads to the formation of primary root which grows inside the soil. The primary roots and its branches constitute the tap root system, as seen in the mustard plant. In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system, as seen in the wheat plant."

The assertion is correct, but the reason is incorrect because the absorption mainly occurs in the region of elongation, where root hairs are formed, not in the region of maturation.

Topic in NCERT: Regions of the Root

Line in NCERT: "These root hairs absorb water and minerals from the soil."

The assertion and reason are both correct, with the reason providing the correct explanation of how leaves are arranged in alternate phyllotaxy.

Topic in NCERT: Phyllotaxy

Line in NCERT: "Phyllotaxy is the pattern of arrangement of leaves on the stem or branch. This is usually of three types alternate, opposite and whorled. In alternate type of phyllotaxy, a single leaf arises at each node in alternate manner. In opposite type, a pair of leaves arise at each node and lie opposite to each other."

The assertion is correct because leaves are the primary site for photosynthesis, and the reason explains how their structure aids this function.

Topic in NCERT: THE LEAF

Line in NCERT: "They are the most important vegetative organs for photosynthesis."

The assertion is false because reticulate venation is found in dicots, not monocots. The reason is true; parallel venation is characteristic of monocots.

Topic in NCERT: Types of Leaves

Line in NCERT: "Leaves of dicotyledonous plants generally possess reticulate venation, while parallel venation is the characteristic of most monocotyledons."

The assertion is false because a flower with only stamens or carpels is unisexual. The reason is correct because a flower with both reproductive organs is bisexual.

Topic in NCERT: THE FLOWER

Line in NCERT: "When a flower has both androecium and gynoecium, it is bisexual. A flower having either only stamens or only carpels is unisexual."

Both assertion and reason are correct, and the reason correctly explains the growth and flowering pattern in racemose and cymose inflorescences.

Topic in NCERT: THE INFLORESCENCE

Line in NCERT: "In racemose type of inflorescences the main axis continues to grow, the flowers are borne laterally in an acropetal succession. In cymose type of inflorescence the main axis terminates in a flower, hence is limited in growth."