Answer:
Beavers and their dams play an important role in nature. Because of the dramatic effects their dams have on surrounding ecosystems, these mammals are considered a keystone species. By constructing dams they create wetlands -- lush environments which attract fish, ducks, frogs and other creatures.
Explanation:
Example of selective breeding: Cows that produce lots of milk. Selective breeding to create more useful varieties of animals and plants is a form of biotechnology that human beings have used for thousands of years. Biotechnology includes any use of science or technology to alter the characteristics of a particular breed or animal.
You have no choices however, A gene pool is defined as a sum total of all the genes present in an inter-breeding population at a specific time. It includes all the alleles of all the loci within the genes of a interbreeding population or species. The composition of the gene pool of a population can change with course of a time due to evolution
B. widely accepted as true. It can be supported by results that are repeatable. It is widely accepted as true, but not proven as a fact.
