Q. The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is:
A) elongating
B) widening
C) differentiating
D) maturing
Explanation
[Solution from source] Protoxylem forms in regions that are still elongating, and its annular and spiral wall thickenings allow the vessels to stretch with the growing organ without breaking. Metaxylem, with reticulate and pitted thickenings, forms later when the organ has stopped elongating and is maturing. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.