The population growth rate is maximum in which of the following countries?

Exponential growth of a species can be expressed as:

The main factor in increasing the population is

The human population growth graph is:

The integral form of the exponential growth equation is $N_{t} = N_{0} e^{rt}$. Identify $A, B, C$,and $D$ from the given equation where:
$A$: Population density after time $t$
$B$: Population density at time zero
$C$: Intrinsic rate of natural increase
$D$: The base of natural logarithms $(2.71828)$

Zero growth of population is indicated by