“Sap wood” is otherwise called

The tissue which participates in the secondary growth is

$A$ : Oldest layer of sapwood lies just outside vascular cambium.

$R$ : Sapwood contains actively conducting vessels and occupies central part of stem.

The waxy substance associated with cell walls of cork cells is or cork cells are impervious to water because of the presence or what is deposited on cork cells

As a tree grows older, which increases rapidly in thickness

When secondary growth in thickness is initiated in a dicot root, which of the following happens first