What is the zero growth phase?

In a forest, there are initially $100$ deer. Over a certain period, $30$ are born and $10$ die. Assuming food is abundant and predators are few, calculate the intrinsic rate of natural increase for that population.

Exponential growth curve is:

The cause of zero growth of population 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 $(2.71828)$

Which one is correct for the logistic model of population growth?
$I.$ Population growth rate increases as the size of the population approaches the carrying capacity.
$II.$ All individuals have the same effect on population growth.
$III.$ There are unlimited natural resources.
$IV.$ As population increases,the competition goes on increasing.
Select the correct combination.