Which type of bacteria does not require oxygen to grow?

The correct answer is associated with anaerobic bacteria, which thrive in environments devoid of oxygen. These organisms can complete their metabolic processes without utilizing oxygen, allowing them to survive and grow in conditions where aerobic or facultative bacteria would struggle. This characteristic is crucial in various biological processes and industrial applications, such as waste treatment and fermentation, where anaerobes play a significant role in decomposing organic matter and producing biogas.

In contrast, aerobic bacteria require oxygen for their growth and metabolic activities, while facultative organisms can switch between aerobic and anaerobic processes depending on their environment. Thermophilic bacteria, on the other hand, are adapted to high-temperature environments but do not inherently categorize themselves by their oxygen requirements. Thus, the defining feature of anaerobic bacteria sets them apart from the other types listed.