Anticlinal divisions in an organ cause its growth in

Periblem gives rise to

$A$. According to Clowes,the root apex consists of an inverted cup-like structure.
$B$. $A$ low amount of $RNA$,$DNA$,and protein is a characteristic of the waiting meristem.
$C$. Cells of the reserve meristem can divide only when the root apex gets injured.

On the basis of the plane of division,the growth forms of meristems have been distinguished as:

Intercalary meristem is a derivative of

Increase in length of the plant axis is caused by: