If biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on .
A) gene flow
B) reproductive isolation
C) hybrid formation
D) gene pool expansion

Option-(B): If biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on reproductive isolation.                            

Explanation:

There is diversity among being and we see that millions of species roam the face of land, all this happens in the tenure of centuries. While the process of evolution or creation of new species happens when a certain specie is kept inside such an environment or a very unique environment that the species is tempted to cross with another form of organism belonging to a different specie, so, this process initiates the creation of new species or organisms having a very different set of characteristics as compared to there ancestors.

The answer is c. they had seedshope this

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait.