An Organism That Grows at the Top of a Tube

Question

An organism that grows at the top of a tube of medium containing thioglycolate is probably a(n)
A) strict aerobe.
B) facultative anaerobe.
C) aerotolerant anaerobe.
D) microaerophile.
E) strict anaerobe.

Accepted Answer

Strict aerobes require oxygen for growth, so an organism growing at the top of a thioglycolate tube, where oxygen concentration is highest, is likely a strict aerobe.