Practice!

Sample Problem

Archaea and Bacteria

(A) come first in the evolutionary tree

(B) are unicellular

(C) are protists

(D) all of the above

Solution

(A) and (B) are correct answers. Archaea and Bacteria can be described as evolutionarily primitive and unicellular. Protists are unicellular and eukaryotic while bacteria are unicellular and prokaryotic; therefore, protists comprise a separate kingdom.