The common ancestors of birds and mammals were very early (stem) amniotes, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered heart of birds and animals are best described as_______.
Which of the following characteristics do biologists use to distinguish bacteria from archaea?
Composition of the molecules that make up their cell walls and membranes
t/f Thin peptidoglycan cell walls are susceptible to penicillin.
The joining together of two prokaryotes with a pilus to transfer DNA is called_____. Term
Which is one of the four criteria that must be met to establish a causative link between a specific microbe and a disease, as proposed by Koch?
The microbial organism must be isolated and grown in a pure culture outside the host organism