What happens to a population when the death rate decreases? A. The birthrate usually increases.
B. The population size usually increases.
C. The population size usually decreases.
D. The birthrate usually decreases.

B. The population size usually increases.

Explanation:

You can predict the growth rate by using this simple equation: growth rate = birth rate – death rate.

If the birth rate is larger than the death rate, then the population grows.

The population size will decrease.

If the birth and death rates are equal, then the population size will not change.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.