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

(N/A) Arithmetic growth
In arithmetic growth,following mitotic cell division,only one daughter cell continues to divide while the other differentiates and matures. $A$ constant linear growth,such as the elongation of roots at a constant rate,is an example of arithmetic growth.
$(b)$ Geometric growth
In geometric growth,both daughter cells derived from mitosis retain the ability to divide and continue to do so. Initially,the growth is slow (lag phase),followed by a rapid increase (exponential phase) due to the exponential increase in cell number,and finally,it slows down due to limited nutrient supply.
$(c)$ Sigmoid growth curve
The growth of living organisms in their natural environment is characterised by an $S$-shaped curve called a sigmoid growth curve. This curve is divided into three phases: the lag phase,the log phase (or exponential phase) of rapid growth,and the stationary phase.
Exponential growth can be expressed as:
$W_{1} = W_{0} e^{rt}$
Where,
$W_{1} =$ Final size
$W_{0} =$ Initial size
$r =$ Growth rate
$t =$ Time of growth
$e =$ Base of natural logarithms
$(d)$ Absolute and relative growth rates
Absolute growth rate refers to the measurement and comparison of total growth per unit time.
Relative growth rate refers to the growth of a given system per unit time,expressed on a common basis,i.e.,per unit initial parameter.