When is speciation complete?

A. When the two populations can no longer interbreed

B. When gene flow increases

C. When an allele becomes fixed

D. When part of the population has a new trait

Answer: A. When the two populations can no longer interbreed

Explanation:

Speciation is a process in which the members of the same population of a species get separated due to geographical, physical, behavioral, and temporal barriers. The separated members develop new traits and becomes a new species.

Among the given options, A. When the two populations can no longer interbreed is the correct option because if the members of the same population will longer interbreed they may experience reproductive isolation from the separated members and with the coarse of evolution they will develop traits which will be responsible for the development of new species. Hence, speciation will complete.

When two populations can no longer interbreed

Explanation