Vegetation grows in a unique way. Describe.

Thigmotropism is best seen in

$A$ single cell in the root apical meristem of maize can give rise to more than $......$ new cells per hour.

Which factor determines the direction of movement of the main root and stem?

$I.$ 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.

Assertion $(S)$: Growth occurs when anabolic processes exceed catabolic processes.
Reason $(R)$: Growth is the result of metabolism.
$(A)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(B)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(C)$ $S$ is true and $R$ is false.
$(D)$ $S$ is false and $R$ is true.