Many types of grass leaves have the ability to roll or unroll because they .....

The stomata in an isobilateral leaf:

Identify the labels $P$,$Q$,and $R$ in the given cross-section of a leaf.

Describe the internal structure of a dorsiventral (dicotyledonous) leaf.

When the conditions are dry,a grass leaf curls inward to minimize water loss due to the pressure of

The epidermis in a dorsiventral leaf:
$(a)$ Covers both adaxial and abaxial surfaces
$(b)$ Is not covered by cuticle
$(c)$ Bears more stomata on the upper side
$(d)$ May even lack stomata on the upper side
Which of the above statements are correct?