When food supply is poor,the rate of growth is

$I.$ Increased vacuolation
$II.$ Cell enlargement
$III.$ New cell wall deposition
Which of the above are the characteristics of the phase of elongation?
Choose the correct option accordingly.

Distribution of growth in a root by marking it at equal intervals with Indian ink was originally studied by

Example of positive geotropism is

The leaves of $Mimosa$ $pudica$ (Sensitive Plant) droop down on touch because

The effect of oxygen supply on growth is