How is it that viruses can be thought of as the "bark" on the tree of life: an important component all across the tree, but not quite like the main branches?
A) Most plant viruses primarily cause a reaction on the outer surface of plant stems.
B) Viruses are smaller than any forms of cellular life.
C) Viruses are only of peripheral importance to life on Earth.
D) Replicating viruses often escape the host through the cell membrane.
E) They have evolved repeatedly from unrelated cellular organisms, not from one another.

Question

Quizplus · Accepted Answer

Viruses are considered akin to the "bark" on the tree of life because they have evolved multiple times from different cellular organisms, indicating they are widespread and integral to life's diversity but do not share a single common ancestor that would place them directly on the main branches of the tree of life.

How Is It That Viruses Can Be Thought of as the "Bark