Which of the following statements is true?
A - A prezygotic reproductive barrier reduces the reproductive capacity of hybrid offspring
B - Both prezygotic and postzygotic mechanisms influence the speciation of a population
C - If two organisms can produce a viable hybrid, the parental organisms are not different species
D - Gametic isolation is a postzygotic reproductive barrier
E - Low hybrid viability is a form of prezygotic isolation
Answer: B - Both prezygotic and postzygotic mechanisms influence the speciation of a population
POSTZYGOTIC reproductive barriers occur after the zygote has formed, meaning they either reduce the viability or the reproductive capacity of the hybrid.
PREZYGOTIC reproductive barriers do not cause speciation since they happen before the zygote is formed.