NEETBotanyAnatomy of Flowering Plants
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In stems, the primary xylem is endarch, whereas in roots, the primary xylem is exarch. Reason (R): In stems, protoxylem lies towards the centre and metaxylem towards the periphery; in roots, protoxylem lies towards the periphery and metaxylem towards the centre. In the light of the above statements
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A).
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A).
- C(A) is correct but (R) is not correct.
- D(A) is not correct but (R) is correct.
Correct answer
A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
Step-by-step solution
The Assertion correctly states the condition of primary xylem in stems (endarch) and roots (exarch). The Reason correctly defines these terms based on the relative positions of protoxylem (first formed primary xylem) and metaxylem (later formed primary xylem). In stems, the protoxylem lies towards the centre (pith) and the metaxylem lies towards the periphery, which is the exact definition of the endarch condition. In roots, the protoxylem lies towards the periphery and the metaxylem lies towards the centre, which