Thioglycollate broth.
Pink color indicates the presence of O₂. (This is visible in the uninoculated tube.)
Match the organisms in the tubes to the following descriptions:

Aerobe
Aerotolerant anaerobe
Facultative anaerobe
Obligate anaerobe

Assume each of the following organisms is in one of the tubes. Match the organisms to the appropriate tube.

Alcaligenes
Escherichia
Clostridium
Enterococcus