Biology - Organisms and Populations Question with Solution | TestHub

Population density at a given time is determined by four basic processes: birth rate ($B$), death rate ($D$), immigration ($I$), and emigration ($E$).

The equation for population density is $N_{t+1}=N_t+(B+I)-(D+E)$.

From this equation, population density decreases when there is a decrease in birth rate ($B$) or immigration ($I$), or an increase in death rate ($D$) or emigration ($E$).

Therefore, a decrease in birth rate and an increase in death rate will lead to a decrease in the population density.

Answer: B and D only