The correct answer is 4.) Eventually they become separate species
A process of formation of a new species from an existing species is called speciation.
When a single species changed into two or more separate species, is called speciation. Speciation can take place due to reproductive isolation. In reproductive isolation, the separated species no longer can interbreed among themselves. This is happened due to mating differences, sterility or environmental barriers which finally results into the adaptive splitting into two species.
D.) ovum. this is because haploid cells are present during mesois, which occurs in the reproductive organs. diploid cells are full counted cells which occurs in mitosis