The time interval between the appearance of two successive leaves or pairs of leaves is termed as:

Sleep movements of leaves in certain plants or photonasty is due to:

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.

Identify the correct and incorrect statements from the following.
$(i)$ $17,500$ new cells are produced per hour by a single maize root apical meristem.
$(ii)$ With the help of length,growth of pollen tube is measured.
$(iii)$ The growth of the leaf is measured in terms of volume.
$(iv)$ Cells in a watermelon may increase in size by up to $3,50,000$ times.

Which one of the following occurs maximum during the exponential growth phase in plants?

Growth of an organ is defined as