Question

horses and zebras can be bred to produce a zorse, which is infertile. which is most likely the reason zebras and horses are considered separate species? they cannot breed. their offspring cannot breed. they look different from each other. they are found in different habitats.

Explanation:

According to the biological species concept, two organisms are of different species if their offspring (hybrid) is infertile. A zorse being infertile shows horses and zebras are separate species. Appearance and habitat are not definitive species - defining factors. Also, we know they can breed as they produce zorses.

Answer:

Their offspring cannot breed.