Tadpoles grow and develop into adult frogs. The time they take to develop depends on the temperature. Tadpoles develop more quickly where it is colder. A species of frog is found in ponds in the hills near a mountain range. Over the past 50 years, scientists have found that the rate of tadpole development in these ponds has steadily increased. Which kind of environmental change most population?
A. Long-term climate change
B. Emergence of a geographic barrier
C. Introduction of other organisms
D. Change in availability of light