Where does the maximum growth in the root occur?

The rate of growth of any organism follows

Describe various conditions or factors necessary for growth.

During which phase is the rate of growth the maximum?

Given below are two statements about plant growth.
Statement $I$: Curve for arithmetic growth is linear.
Statement $II$: Curve for geometric growth is exponential.
In the light of the above two statements,choose the most appropriate answer from the options given below.

Movements of leaves of sensitive plant, $Mimosa \text{ } pudica$, are due to