Question

the overall population of a species decreased. what could have occurred to make this happen?
the immigration rate increased, while the death rate decreased.
the birth rate decreased, while the death rate increased.
the carrying capacity increased, while the immigration increased.
the emigration increased, while the birth rate increased.

Explanation:

Population size is affected by birth rate, death rate, immigration, and emigration. A decrease in birth rate and an increase in death rate would lead to a decrease in population. An increase in immigration or birth rate alone or with other positive - population factors would not cause a decrease.

Answer:

The birth rate decreased, while the death rate increased.