What Is Life? 2nd Edition by Jay Phelan

Exercise 34

In a population in which a trait is exposed to stabilizing selection over time:
A) neither the average value nor the variation for the trait changes.
B) both the average value and the variation for the trait increase.
C) the average value increases or decreases, and the variation for the trait decreases.
D) the average value for the trait stays approximately the same, and the variation for the trait decreases.
E) the average value for the trait stays approximately the same, and the variation for the trait increases.