Conjoint collateral closed vascular bundle is found in

In which organ is this type of vascular bundle found?

In how many of the following plant organs are open vascular bundles found? Dicot root,Dicot stem,Monocot root,Monocot stem,Dicot leaf,Monocot leaf.

Well developed pith is found in

Reduction in vascular tissue,mechanical tissue,and cuticle is a characteristic of ..........

Identify $P, Q,$ and $R$ in the given internal structure.