Excision is the right answer :)
It was used till the 1960s. Hope i helped.
Answer;
-Gametic Isolation
Explanation;
-Gametic isolation is a type of prezygotic barrier where the gametes (egg and sperm) come into contact, but no fertilization takes place.
-In Gametic isolation is when sperm of one species may not be able to fertilize the eggs of another species. For instance, sperm may not be able to survive in the reproductive tract of females of the other species, or biochemical mechanisms may prevent the sperm from penetrating the membrane surrounding the other species' eggs.
