Cork tissue arises from

Tyloses,an outgrowth from ray or axial parenchyma cells into the lumen of a vessel,which partially or completely blocks the cavity,are present in:

Read the components $a$ to $d$ given in the note and identify the correct sequence of components from the outside to the inside of a mature stem:
$(a)$ Secondary cortex
$(b)$ Wood (Secondary xylem)
$(c)$ Secondary phloem
$(d)$ Phellem (Cork)

Identify the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem.
$I.$ Secondary cortex
$II.$ Autumn wood
$III.$ Secondary phloem
$IV.$ Phellem

Age of a tree can be estimated by :

Cambium is essential for grafting in plants because