Which layer in dicot stem is rich in starch grains?

Conjoint collateral vascular bundles and eustele are present in ..........

$A$ common difference between the stem and the root is that the xylem in the stem is ...... .

Select the correct option$(s)$ from the following statements:
$(i)$ Fibers are thin-walled,elongated,and pointed cells.
$(ii)$ Water-containing cavities (lysigenous cavities) are found in the vascular bundles of monocot stems.

No secondary growth occurs in monocot stem because

Innumerable vascular bundles,lack of cambium and lack of a well demarcated pith is found in: