According to the theory of mitochondria in cells today are the descendants of aerobic prokaryotes that used oxygen to generate energy.

endosymbiosis

Explanation:

The theory of endosymbiosis states that mitochondria in cells are once the descendants of aerobic prokaryotes. These prokaryotes used oxygen in order to generate energy. The mitochondria and the chloroplast are among the most important organelles that support endosymbiosis.

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the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands