The correct answer is geographic isolation.
Geographic isolation refers to a term, which signifies towards a population of plants, animals, or other species, which are distinguished from exchanging genetic substance with other organisms of the same species. Usually, geographic isolation is the outcome of a coincidence or an accident.
It is considered that geographic isolation is a usual way for the procedure of speciation to start: mountains rise, rivers change course, organisms migrate, continents drift, and what was once a spontaneous population is differentiated into two or more smaller populations.
Geographic isolation refers to the distinction of two populations of the similar species or breeding group by a physical barrier, like a body of water or a mountain. Geographic isolation may eventually result in the populations becoming distinct species by adaptive radiation.
