In allopatric speciation, species usually form ____.

A) abruptly
B) in proportion to the parental stock
C) rapidly, but are then reduced by environmental factors
D) gradually over rather long periods of time
E) in the same homeland

Allopatric Speciation

The formation of new species in populations that are geographically isolated from one another.

Environmental Factors

External influences from the surrounding environment that can affect the growth, development, and survival of organisms.

Parental Stock

The breeding animals or plants used in agriculture or aquaculture, from which offspring are produced for specific qualities or production purposes.