The correct answer is option 2: Composting. Composting is a biological process where both aerobic and anaerobic organisms break down organic matter such as food waste, yard trimmings, and other biodegradable materials. During composting, aerobic bacteria and fungi decompose the organic matter in the presence of oxygen, converting it into humus-rich soil. These aerobic organisms require oxygen to carry out the decomposition process.

On the other hand, anaerobic bacteria can also play a role in composting when the oxygen levels are low or depleted, such as in the center of a large compost pile. Anaerobic bacteria break down the organic matter in the absence of oxygen, producing by-products like methane gas.

Therefore, composting is the biological process in which both aerobes and anaerobes degrade organic matter.