Define and explain the following terms related to plant growth:
$(1)$ Absolute growth
$(2)$ Relative growth

(N/A) $(1)$ Absolute growth: It refers to the total growth of a plant or its organ measured over a specific period of time. It is expressed as the difference between the final size and the initial size of the plant organ.
$(2)$ Relative growth: It is the growth of a given system per unit time expressed on a common basis,i.e.,per unit initial parameter. It is calculated as the ratio of the increase in size to the initial size,often expressed as a percentage.