Which of the following is a by-product of anaerobic decomposition?

The by-product of anaerobic decomposition is biogas, which primarily consists of methane and carbon dioxide. Anaerobic decomposition occurs when organic matter breaks down without the presence of oxygen, such as in a landfill environment. During this process, microorganisms digest the organic matter, resulting in the production of biogas as they metabolize the available substrates. This biogas can be captured and utilized as a renewable energy source, contributing to energy recovery initiatives in waste management.

Other options do not represent by-products of anaerobic decomposition. For instance, electricity is not a direct by-product of this process, although biogas can be converted into electricity. Oxygen is produced during aerobic decomposition, not anaerobic. Solid mineral deposits can result from various processes related to the breakdown of organic matter but are not directly generated during anaerobic decomposition itself.