Question

Small pores on the epidermis of leaves are:
A) Stomata
B) Nodes
C) Tubes
D) None of the above

Answer 1

Hint: Small pores on the epidermis of leaves provide an exchange of gases between the outside air and the branched system of interconnecting air canals within the leaf.

 Complete answer: Stomata are the microscopic openings or pores in the epidermis of leaves and young stems. Stomata are generally more numerous on the underside of leaves. They provide for the exchange of gases between the outside air and the branched system of interconnecting air canals within the leaf. Stomata are present in all land plant. In vascular plants, the number, size and distribution of stomata varies widely. Carbon dioxide helps in photosynthesis is present in the atmosphere at a concentration of about 400 ppm. Most of the plants require the stomata to be open during the daytime because in night time plants exhale more O2 (Oxygen).
Nodes are not the small pores present on the epidermis of the leaves instead they are the link between leaves and the main branch. They also help in transporting raw material from the main branch to the leaves. Tubes run through plants stem and root. Tubes carry water, minerals and other sources of raw materials to prepare food by photosynthesis. The most common example of tubes is Xylem and Phloem.

Thus, the correct option is A. i.e., Stomata.

Note: There is a little evidence of the evolution of stomata in the fossil record, but they had appeared in land plants by the middle of the Silurian period. They may have evolved by the modification of conceptacles from plant alga-like ancestors.