Question: what are the 3 types of oxygen requirements in bacteria?
Answer: Aerobes: Aerobes grow in ambient air, which contains 21% oxygen and small amount of (0.03%) of carbon dioxide. ... 
Obligate aerobes: They have absolute requirement for oxygen in order to grow. ... 
Anaerobes: Usually bacteria of this group can not grow in the presence of oxygen, oxygen is toxic for them.