Each of the Following Are Characteristics of Microorganisms That Pose

Each of the following are characteristics of microorganisms that pose unique challenges to their study EXCEPT

A) the fact that they must be viewed through a microscope rather than the unaided eye.
B) the fact that many do not have membrane-enclosed nucleus or other organelles.
C) the fact that they often exist in complex communities and individual species may be difficult to isolate from others.
D) the fact that they usually must be grown and studied under somewhat artificial conditions in vitro rather than in their natural habit.