Reproductive isolation occurs when A- some catastrophic event greatly reduces the size of the population

B- The gene pool of different populations have become very diversified

C-members of different populations can no longer meet successfully

D-small numbers of individual moves and starts in new population

The correct answer is - C. members of different populations can no longer meet successfully.

Explanation:

Reproductive isolation is the process that occurs when two or more species or populations are not able to interbreed. The mechanisms or properties that are used to preventing individuals of separate species from mating called Reproductive isolation mechanisms.

The different barriers can cause this reproductive isolation such as different mating seasons. These barriers could be behavioral or temporal or ecological isolations.

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.