Documents Trait Pelycosaurs Therapsids Cynodonts Posture:sprawlingintermediateupright

Trait Pelycosaurs Therapsids Cynodonts Posture: sprawling intermediate upright Teeth: weakly heterodont increasingly heterodont strongly hetero Palate: no secondary palate…

Documents Study traces AIDS virus origin to 100 years ago

âResearchers took advantage of the fact that HIV mutates rapidly. So two strains from a common ancestor quickly become less and less alike in their genetic material over…