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

Give reasons for:
$(a)$ Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuoles.
$(b)$ Intercellular spaces are absent in sclerenchymatous tissues.
$(c)$ We get a crunchy and granular feeling when we chew pear fruit.
$(d)$ Branches of a tree move and bend freely in high wind velocity.
$(e)$ It is difficult to pull out the husk of a coconut.

Differentiate between voluntary and involuntary muscles. Give one example of each type.

State whether the following statement is true or false:
The brain,spinal cord,and nerves are all composed of muscular tissue.

Explain the basic characteristics for the classification of permanent tissues in plants.

Flexibility in plants is due to