Which term refers to bacteria that do not require oxygen to survive?

• A. Bacteria
• B. Algae
• C. Anaerobic bacteria
• D. Alkalinity

Answer: (C)

Oxygen requirements of bacteria determine how they grow and survive in different environments. Anaerobic bacteria do not require oxygen for growth; in fact, many cannot tolerate oxygen and perform their metabolism in oxygen-free conditions. This makes them the organisms that thrive in environments like anaerobic digesters, where organic matter is broken down without air and methane can be produced.

The other terms don’t describe this trait. A general term like bacteria is too broad to identify their oxygen needs, algae are typically photosynthetic organisms, and alkalinity refers to a water’s chemical property, not to living microorganisms’ oxygen requirements.