a. Polyarch xylem

b. Well-developed pith

c. Radial vascular bundle

Solution:

(a) Polyarch xylem is present in monocot root. When many strands of xylem in the stele region are present, it is referred to as polyarch condition-a characteristic feature of monocot root.

(b) Well-developed pith is present in dicot stem and monocot roots. Dicot stem and monocot roots have well-developed pith formed of the parenchymatous cell with intercellular spaces.

(c)Radial Vascular bundle is present in roots. The radial Vascular bundle includes xylem and phloem, and these are present in separate radii of the roots