List five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agricultural/horticultural applications of any one of them.

List four plant hormones. Write one function of each.

List two types of the transport system in human beings and write the functions of any one of these.

Plant Growth|The Discovery of Plant Growth Regulators|Physiological Effects of Plant Growth Regulators Auxins|Physiological Effects of Plant Growth Regulators Gibberellins|Physiological Effects of Plant Growth Regulators Cytokinins|Physiological Effects o