Which process does not require oxygen?

The process that does not require oxygen is anaerobic. Anaerobic processes occur in environments where oxygen is absent and rely on alternative metabolic pathways to produce energy. This is significant in various biological and chemical contexts, such as fermentation, where organisms like yeast convert sugars into alcohol and carbon dioxide without using oxygen.

In contrast, aerobic processes, as the name suggests, require oxygen for growth and energy production, as seen in cellular respiration where glucose is broken down using oxygen to release energy. Photosynthesis, primarily associated with plants, involves the use of light and carbon dioxide, but it also functions in an aerobic manner since some of its byproducts, like oxygen, are crucial for other aerobic processes. Respiration is a general term that encompasses both aerobic and anaerobic processes, but aerobic respiration specifically necessitates oxygen for energy generation. Thus, recognizing that anaerobic specifically indicates a lack of oxygen is key to understanding why it is the correct choice.