Answer:
B Physical separation of populations prevents interbreeding and mixing of gene pools.
Explanation:
Geographic isolation means two populations are unable to reproduce with one another. This means that over time, the variation in the gene pool will be different for one group compared to the other, and the species will genetically diverge from one another. resulting in speciation.
Lasting genetic similarities make the two bears biological sister species, more closely related to one another than to any others. ... But Ursus maritimus has also evolved to match its polar environment, growing a longer snout than brown bears' and larger, paddle-like paws, both of which aid polar bears in hunting seals.