申論題

2. Why effective population size is usually smaller than the actual census size? (Circle all correct answers)(5%) (A) Migration between populations. (B) Variation in the number of progenies produced by females, males, or both. (C) Unequal number of males and females that produce offspring. (D) Natural selection increases variation in progeny number. (E) Fluctuations in population size. (F) Mutations.