Answer:
B. Changes in the size of a mouse population after hawks, a main predator of mice, are introduced into the area where the mice live
Explanation:
A community is defined as a group of populations of two or more different species which inhabit the same area at a certain time.
Community ecology is the study of the interactions between species in communities through time on a certain place. It includes the study of the distribution, structure, demography, and interactions between populations.