Viruses are thought to have evolved
A) only once in evolutionary history.
B) from escaped genomic components.
C) from reduced cellular components.
D) only twice in evolutionary history.
E) Both a and b

Question

Quizplus · Accepted Answer

The escape hypothesis proposes that viruses evolved from genetic elements (such as plasmids or transposons) that gained the ability to move between cells. Therefore, viruses are thought to have evolved from escaped genomic components. Option A is incorrect because there is evidence of multiple independent origins of viruses. Option C is incorrect because viruses are actually composed of complex and diverse components, not reduced ones. Option D is incorrect because there is evidence of more than two independent origins of viruses. Option E is partially correct, but only option B provides the correct explanation for virus evolution.

Viruses Are Thought to Have Evolved