Relatively Little Is Known About Many Obligate Anaerobes

Multiple Choice

Relatively little is known about many obligate anaerobes. Why might this be so?

A) There are far more obligate aerobes in any environment, so it is much easier to study them.
B) It is difficult to provide the right atmospheric environment to cultivate obligate anaerobes, so it's been harder to study them.
C) Only obligate aerobes cause disease, so we have had little reason to study obligate anaerobes.
D) The majority of obligate anaerobes are very nutritionally fastidious, which makes it difficult to study them.
E) It is difficult to provide the right temperature to cultivate obligate anaerobes, so it's been harder to study them.