Two populations are said to be isolated if there is no longer any Gene Flow between them.
Phytoplanktons are also called microalgae. They are the foundation of the aquatic food web and the primary producers. They feed everything from microscopic to multi-ton whales. Thus, the answer to the question above is letter B. Provide basis of food chains.
“Populations evolve through a process known as natural selection which allows individuals with beneficial traits for survival to breed with other individuals who share those traits, eventually leading to offspring who only exhibit those superior traits.” -from: https://www.thoughtco.com/only-populations-can-evolve-1224608
Hope this helps! :)
