In a mature dicot stem which has undergone seconday growth, youngest layer of secondary xylem is situated

Options

A. in between pith and primary xylem
B. just outside the vascular cambium
C. just inner to the vascular cambium
D. just inner to the phellogen.

Answer

C

Explanation

The cambial ring present between primary xylem and primary phloem becomes active and begins to cut of new cells, both towards the inner and the outer sides. The cells cut off towards pith mature into seondary xylem and the cell cut off towards periphery mature into secondary phloem.