Imagine You Are Studying Leaf Size in a Large Population

Multiple Choice

Imagine you are studying leaf size in a large population of plants over several years. In one year of your study there is a below-average amount of rainfall, and the following year the average leaf size in the population is smaller than before. However, the amount of variation in leaf size is the same and the population size doesn't change. Other scientists have done experiments showing that small leaves are better adapted to dry conditions than large leaves. What has most likely occurred?

A) genetic drift
B) directional selection
C) stabilizing selection
D) the founder effect
E) disruptive selection