Along the length of a river, there exists a species of green sunfish. In order to provide electricity to area homes, a hydroelectric dam is built that separates the lower river area from a newly formed lake above. After many, many years, the green sunfish in the river and lake are sampled and found to be very different. Which of the scenarios listed below is the best hypothesis to explain the changes observed? a. directional selection.
b. disruptive selection.
c. stabilizing selection.
d. sexual selection.