Anaerobic bacteria are:

• A. Bacteria that require oxygen to survive
• B. Viruses
• C. Bacteria that do not require oxygen to survive
• D. Algae

Answer: (C)

Anaerobic means bacteria that do not require oxygen to survive. They can live and metabolize in environments without oxygen, and in wastewater treatment they’re the ones driving digestion in sealed, oxygen-free systems to break down organic matter and sometimes produce methane. This is different from bacteria that need oxygen (aerobic bacteria), which require oxygen for their energy processes. Viruses aren’t bacteria, and algae are not bacteria either, so they don’t fit the description. So, anaerobic bacteria are those that do not require oxygen to survive.