MDRAO Practice Exam 2026 – Complete Exam Prep Resource

The most suitable choice is anaerobic bacteria, as these organisms are specifically defined by their ability to survive and thrive in environments devoid of oxygen. Anaerobic bacteria have evolved metabolic processes that do not require oxygen. Rather, they may utilize alternative pathways such as fermentation or anaerobic respiration, which allows them to derive energy from organic compounds without the need for oxygen.

Facultative anaerobes, on the other hand, are capable of surviving in both the presence and absence of oxygen. While they can switch to anaerobic processes when oxygen is not available, they are still dependent on oxygen for optimal growth. Aerobic bacteria exclusively require oxygen to survive; their metabolic processes are entirely dependent on the presence of oxygen.

The inclusion of "all types mentioned" would not be accurate, as it implies that all listed bacterial types can survive without oxygen, which is not true. Each type has distinct requirements for oxygen, making anaerobic bacteria the correct answer to the question regarding which type survives without it.