Which greenhouse gas is a byproduct of anaerobic respiration?

Methane is a greenhouse gas that is indeed a byproduct of anaerobic respiration, which occurs in environments with little to no oxygen, such as in wetlands, rice paddies, and the intestines of certain animals. During anaerobic respiration, microorganisms metabolize organic matter and produce methane as a waste product. This process is carried out by a group of organisms known as methanogens. Methane is significantly more effective at trapping heat in the atmosphere compared to carbon dioxide, making it a potent greenhouse gas.

While carbon dioxide is also a greenhouse gas and is produced during aerobic respiration, it is not produced during anaerobic processes. Ozone, on the other hand, is formed in the atmosphere through chemical reactions involving sunlight and is not directly a product of respiration. Nitrous oxide is another greenhouse gas, but it primarily results from agricultural practices and also from specific biochemical processes, rather than being a direct byproduct of anaerobic respiration. Thus, methane is the correct response as it specifically relates to anaerobic conditions.