Which of the following increases in the absence of light?

Phytotron is

In $......$,growth occurs throughout life,whereas in $......$,growth is observed only up to a certain age.

The $S$-shaped growth curve and 'grand period of growth' may change with:

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.

In plants, growth is observed ..........