Which of the following is the most important parameter chosen for assessing impacts of any biotic or abiotic factor on population growth?

The correct option is B ‘r’
The intrinsic rate of natural increase, (r) $=$ per capita birth rate (b) $-$ per capita death rate (d) Intrinsic rate of natural increase takes into account both the birth rate and death rate. These are influenced by abiotic and biotic factors and impact the growth of the population.

Population density (N) refers to the number of individuals in a given area.

Mortality (D) is the number of deaths in a population in a given time period.

Natality (B) is the number of births in a population in a given time period.

Final answer
(A) ‘r’