What is the term for the maximum population size of a species that an environment can sustain indefinitely,given the available resources?

If non-limiting conditions are provided,then what will happen?

Slow population growth was due to a high birth rate and a high death rate,which characterized the stage of:

$A$ population in a habitat with limited resources shows four phases of growth. Identify the correct sequence of growth.

Read the following statements and determine how many of them are correct:
$(1)$ Population is the total number of individuals of a species in a given area at a given time.
$(2)$ Developed countries show a low birth rate.
$(3)$ An equal proportion of reproductive and post-reproductive age individuals indicates a stable population.
$(4)$ In the presence of limited resources,the growth curve is sigmoid ($S$-shaped).

Assertion: In a sigmoid growth curve,the population finally stabilizes itself.
Reason: Finally,the death rate increases more than the birth rate.