Which of the following will decay faster if exposed freely?

In $Barley$ stem,vascular bundles are:

The transverse section of a plant material shows the following anatomical features under microscope $:-$
$(a)$ Collenchymatous hypodermis
$(b)$ Sclerenchymatous pericycle located just above phloem bundles in semi-lunar patches.
$(c)$ Vascular bundles are arranged in a ring.
$(d)$ Vascular bundles are conjoint & open.
Plant material should be :

The vascular bundles in the stems of most of dicots are conjoint,collateral and open. In each of these bundles

What is the function of the hypodermis?

In which of the following,the cortex,endodermis,pericycle,and pith are not clearly distinguishable?