試題詳解

21. The evolution of organisms that use oxygen in their respiration was possible only because of the action of a group of bacteria that produced oxygen and changed the Earth's atmosphere from an anoxic one to one rich in oxygen. That group of bacteria was:
(A) actinobacteria
(B)spirochaetes
(C)proteobacteria
(D)Staphylococcus
(E) cyanobacteria