Question: What happens if a breeder crosses a horse with a donkey?
Option 0: The two species, horse and donkey are closely related species and can be cross-bred successfully to produce offspring, however the offspring will speak different languages and family discord may result. There would be little benefit from such practice, unless the goal is family discord, or in extreme cases, extinction and compromised health.
Option 1: The two species, horse and donkey, are not the same but are related species. They can be bred together and produce off spring, but the offspring will be sterile. This is a natural built in barrier to protect both species from extinction and compromised health.
Answer: 1