Water-containing cavities in vascular bundles are found in

In monocot plants,the 'girdling experiment' does not yield any results due to:

Vascular bundles in monocotyledons are considered closed because

The transverse section of a plant shows the following anatomical features:
$(a)$ Large number of scattered vascular bundles surrounded by bundle sheath.
$(b)$ Large conspicuous parenchymatous ground tissue.
$(c)$ Vascular bundles conjoint and closed.
$(d)$ Phloem parenchyma absent.
Identify the category of plant and its part.

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

Which of the following parts of a dicot stem contains tissue that provides mechanical strength to the young stem?