Question

What causes observable differences to arise between separated populations over time, dividing a species into races?

Options

• Gene exchange with members of other species

• The inability of individuals from different populations to interbreed

• Environmental forces vary by locality

• Complete discontinuity of variation among members of the same species

Answer 1

Environmental forces vary by locality, so separated populations develop observable differences over time. These differences divide a species into geographical sub-units called races.