Which of the Following Most Closely Resemble the Earliest Ancestor

Question

Which of the following most closely resemble the earliest ancestor of all animals?
A) colonial, flagellated protists
B) unicellular protozoa
C) colonial algae
D) gram-negative bacteria

Accepted Answer

The earliest ancestor of all animals is thought to resemble colonial, flagellated protists. This is because animals are multicellular eukaryotes, and the transition from unicellular to multicellular life is believed to have occurred in a stepwise fashion, with colonial organisms representing an intermediate stage. Flagellated protists, being eukaryotic and having the ability to form colonies, provide a plausible model for the ancestors of multicellular animals.