In a Very Large Population, a Quantitative Trait Has the Following

Multiple Choice

In a very large population, a quantitative trait has the following distribution pattern:

-If the curve in the previous figure shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations. Which of the following is (are) probably occurring?
1) immigration or emigration
2) directional selection
3) adaptation
4) genetic drift
5) disruptive selection

A) 1 only
B) 4 only
C) 2 and 3
D) 4 and 5
E) 1, 2, and 3