The New England cottontail is the only rabbit native to New England. Current populations are small and isolated because of habitat loss. Scientists are concerned about the possible extinction of the New England cottontail. Which of the following statements explains why having small and isolated populations puts these rabbits at risk for extinction? A-Diet requirements of the rabbits are changed, making the emigration rate increase.

B-Male-to-female ratios in the populations are changed, making the birth rate fall to zero.

C-Genetic variation is decreased, making the populations less able to adapt to environmental changes.

D-Immigration is increased, making it harder for the rabbits to successfully compete for resources.