Amolecule that can be used as a molecular clock has a neutral mutation rate of one mutation per 20 million years. how many years ago did two species share a common ancestor if the molecules found in these two species differ by a total of six mutations?

Deserts (especially true deserts) are not easy places for animals to live. animals who live in them often have special features that them survive. which adaptation would be for this group of animals? a) keen eye sight b) short, narrow legs c) tolerate heat d) webbed feet

Animal cells have which of the following characteristics? select all that apply.

What is the anatomical location of the kidneys to the intestines.