The Archaea Are

Multiple Choice

The Archaea are

A) primarily ancient organisms that have not evolved very much in the last billion years.
B) phylogenetically diverse, but functionally restricted to extremophiles and chemolithotrophs.
C) diverse microorganisms that inhabit almost every environment on Earth, including the colon of humans and other mammals.
D) functionally diverse, but restricted to thermophilic or hyperthermophilic environments.