Answer:
geographical isolation
Step-by-step explanation:
one way a new species ma form is by geographical isolation.
Geographical isolation is a form of reproductive isolation in which a physical barrier separates two population of similar species. Each population then go on to become a new species.
Reproductive isolation itself is a mechanism of speciation in which organisms are prevented from producing offspring through mating or produce an invalid offspring if mating and fertilization cannot be prevented from taking place.
When two population of the same species become geographically isolated, each population will follow different evolution path and then become new species.