Susan suffered from a heart attack. when the doctors tested the heart muscle they found that she had an increased ratio of lactic acid to pyruvic acid in her heart. what does this say about the availability of oxygen in her heart muscle cells? the heart cells must have received too much oxygen. the heart cells had not received adequate oxygen supply. the heart cells had a build up of carbon dioxide, poisoning her cells. the heart cells had too much carbon dioxide build up.

(me out over the last several centuries, scientists have made the following broad observations while investigating several branches of the life sciences: -the fossil record shows that different types of organisms have existed at different times in earth's history. -many organisms have similar body structures that seem to be adapted to different ways of living in their environment. -organisms of different species often share similarities in stages of embryonic development. -many species share genetic similarities, and almost all organisms use the same basic building blocks to construct proteins. -often, the extent of two species' similarities can be predicted from their geographic closeness to each other. -a great deal of change has been observed among species that have experienced strong selective pressures through many generations. scientists have carefully considered and rigorously tested the observations listed above. when scientists offer a of these observations, they are making 1.) testable explanation, deductive explanation 2.) scientific interference, scientific law