Which of the following exerts the Richmond-Lang effect,i.e.,prevents the loss of chlorophyll?

Cytokinin is a hormone whose main function is

Zeatin is a

Study the following statements:
$I.$ Cytokinins are formed primarily in roots.
$II.$ Auxin and cytokinin are antagonistic in apical dominance.
$III.$ Kinetin (a modified $DNA$ purine) was discovered from herring sperm.
$IV.$ Zeatin is auxin.
$V.$ Zeatin was firstly extracted from herring.
Choose the incorrect one.

The name 'zeatin' was given by:

From your knowledge of physiology,can you think of some methods to increase the life span of cut plants in a vase?