Plant movement in response to diffuse stimulus of light is

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.

Opening of flower is an example of

Tendrils exhibit/twining of tendrils is due to

$A$ clinostat is an instrument used in experiments related to:

Identify two of the following phytohormones,which regulate the stomatal movements?
$I.$ $IAA$
$II.$ $GA_3$
$III.$ $Zeatin$
$IV.$ $ABA$