A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true?
A) The populations will not be able to interbreed because they are different species.
B) Different species cannot interbreed.

The answer is A - The populations will not be able to interbreed because they are different species and different species cannot interbreed

Explanation:

The population of birds become reproductively isolated because they are different species and different species are unable to interbreed. This is as a result of barriers which are called mechanisms of reproductive isolation which involves mechanisms, behaviors and processes that are critical for speciation. In reproductive isolation the different species are able to live in the same are but their properties and characteristics do not allow them interbreed to produce healthy and sterile offspring.