Approximately How Many Species Have We Described Out of the Species

Multiple Choice

Approximately how many species have we described out of the species alive today?

A) We have described almost all of the species on Earth.
B) We have described about one-eighth of the species on Earth.
C) We have described about one-quarter of the species on Earth.
D) We have described about half of the species on Earth.
E) We have described only a small fraction of the species on Earth.