Answer: Allopatric speciation
Step-by-step explanation:
Allopatric speciation refers to the rise of new distinct species of offspring from parental organisms that DO NOT live in the same territory, that is geographically isolated and thus unable to crossbreed.
Definitely, the emergence of healthy and hybrid offsprings from the TWO species of antelope, from Africa and Asia, breed together in the Zoo could be explained by ALLOPATRIC SPECIATION.