What does 'anaerobic' mean in biological terms?

In biological terms, 'anaerobic' refers to conditions or processes that occur in the absence of oxygen. This characteristic means that certain organisms or cellular processes can thrive or function without relying on oxygen as a critical component for energy production.

Anaerobic respiration, for instance, is a metabolic process that allows cells to generate energy when oxygen is not available. While some anaerobic processes can be beneficial for specific organisms, they can also produce byproducts such as lactic acid or ethanol, which may be harmful in high concentrations. This clarifies why the definition that emphasizes the lack of oxygen aligns well with the concept of anaerobic conditions in biology.

Additionally, other options pertain to other aspects of cellular respiration or activity that involve oxygen, such as aerobic processes, and therefore do not accurately reflect the meaning of 'anaerobic.'