Name the tissue which is present in the veins of leaves.

Why do tracheids and vessels have tubular structures?

The chemical present in the walls of bark of the tree which makes them impervious to gases and water is

What are the functions of the stomata?

Cork cells are made impervious to water and gases by the presence of

Fill in the blanks:
$(a)$ Cork cells possess ........... on their walls that make them impervious to gases and water.
$(b)$ .................. have tubular cells with perforated walls and are living in nature.
$(c)$ Bone possesses a hard matrix composed of ............... and ............. .