A facultative anaerobe.
Step-by-step explanation:
Anaerobes are organisms which can produce energy via the process of fermentation in the absence of oxygen. The anaerobes can be classified as facultative anaerobes and obligate anaerobes.
Facultative anaerobes are those which can carry out respiration in presence of oxygen but can choose to follow the fermentation pathway if oxygen is absent. Fermentation also uses glucose.
Aerobic respiration produces 32 molecules of ATP from one molecules of glucose while fermentation produces only 2 molecules of ATP . Thus when the organism switches to fermentation pathway it utilizes more and more glucose to reach its energy demands.
Considering all the above points we can conclude that observations indicate that the organism is a facultative anaerobe.