The shedding of leaves,flowers,or fruits due to a change in the hormonal balance in plants is referred to as:

$I.$ More female flowers in cucumber
$II.$ $\alpha$-amylase production in barley grain
$III.$ Acceleration of fruit ripening in tomato
$IV.$ Delay in sprouting in potato tubers
From the given effects,identify the effects of ethylene and choose the correct option accordingly.

Which combination of gases is suitable for fruit ripening?

$A$ farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant growth regulator can be applied to achieve this?

Select the correct option for Ethephon.

Horizontal growth of seedling,swelling of axis and apical hook formation in dicot seedling are associated with$:-$