Why does meiosis go through steps twice and divide twice?

Which osmotic and ionic strategies must marine teleost fishes employ?

Use the drop-down menu to match the following definitions to the corresponding terms. the total variety of organisms that live in the biosphere a group of organisms that breed and produce offspring that can breed all of the biotic and abiotic factors in an area

Scientists discover two populations of mice on either side of a major river. the two populations have almost identical genes but the mice from one side cannot breed with mice from the other. this is most likely because