Vascular bundles in which phloem is found on both sides of xylem are called:

Consider the following structures and select the structures which form the stele.
$(A)$ Endodermis
$(B)$ Pericycle
$(C)$ Vascular tissue system
$(D)$ Pith

Nucleus is absent in

Assertion $:-$ Collenchyma forms the hypodermis of dicot stem.
Reason $:-$ This is the reason for flexibility of young dicotyledonous stems.

$A$ vascular bundle is considered closed when:

The most primitive type of stele is