Different growth phases result in a

Phytotron is a facility to

Growth of the plant is

Developing embryo (in vitro) shows

Growth in plants is measured by the increase in
$I.$ Fresh weight. $II.$ Dry weight
$III.$ Length,area and volume $IV.$ Cell number
Choose the correct option.

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.