Why is reproductive isolation required for a speciation to occur ?

Explanation:

Option A is right If populations can interbreed, they are considered as one species.

Speciation is the formation of new and distinct species in the course of evolution. It involves the splitting of a single species into two or more genetically independent species, even if they cannot mate each other due to their physical barrier.

Reproductive isolation means the given group cannot mate with each other because of their physical barrier.

Reproductive isolation is required for speciation to avoid mating because natural selection want them to evolve differently.

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