What type of cycle includes the processes involving animal waste and decomposition?

The nitrogen cycle is the correct choice because it specifically encompasses the processes involving animal waste and decomposition. In this cycle, nitrogen in various forms is converted between different states, including organic forms found in living organisms and inorganic forms in the soil and atmosphere.

When animals excrete waste, it typically contains nitrogenous compounds that are broken down by decomposers, such as bacteria and fungi. These decomposers convert the waste into ammonia, which can then be further transformed into nitrates and nitrites through nitrification. These processes play a critical role in recycling nitrogen, which is an essential nutrient for plant growth. Ultimately, plants absorb these forms of nitrogen, and the cycle continues as animals consume the plants.

In contrast, the oxygen cycle involves the movement of oxygen through the environment, primarily related to photosynthesis and respiration, and does not focus significantly on animal waste. The carbon cycle deals mainly with the flow of carbon among the atmosphere, oceans, soil, and living organisms and is not specifically about animal waste or decomposition. The life cycle refers more broadly to the stages an organism goes through during its lifespan, rather than nutrient recycling processes. Therefore, the nitrogen cycle is the most appropriate answer in relation to the processes mentioned in the question.