The process of growth is determined by

Which process is essential for the growth of an organism?

Describe briefly:
$(a)$ Arithmetic growth
$(b)$ Geometric growth
$(c)$ Sigmoid growth curve
$(d)$ Absolute and relative growth rates

Constantly dividing cells,both at the root apex and shoot apex,represent:

Length of the stem at time $0$ is $20 \ cm$. The arithmetic growth rate is $30 \ cm$ per day. What is the length of the stem at the end of the $7^{th}$ day (in $cm$)?

The first step in the process of plant growth is $.......$.