Of all the possible amino acids, all living organisms make use of only the same 20 amino acids. This supports the idea that
A) all living things are derived from a single common ancestor.
B) bacteria, animals, and plants developed independently.
C) natural selection drives evolution.
D) only a limited number of DNA mutations are possible.
E) only 20 amino acids exist on Earth.

Question

Quizplus · Accepted Answer

The universal use of the same 20 amino acids by all living organisms suggests a common origin, supporting the idea of a single common ancestor from which all life descended. This is a key piece of evidence for the theory of evolution.

Of All the Possible Amino Acids, All Living Organisms Make