Answer:
The type of evidence is Mechanical incompatibility.
Step-by-step explanation:
Copulation is often impossible between different animal species because of the incompatible shape and size of the genitalia.It is called mechanical incompatibility.
This isolation prevents species that diverge from interbreeding thus they lo longer able to mate with each other.
Here morphological difference takes place which ultimately leads to behavioral isolation and thus no mating takes place.
Here snail can not mate because their morphological structures are incompatible.