Final answer:
Animals return water to the atmosphere through respiration, which is the release of water vapor when animals exhale.
Step-by-step explanation:
Animals return water to the air through respiration. When animals exhale, they release moisture in the form of water vapor into the atmosphere.
Transpiration is the process through which plants release water vapor into the air through their leaves. While both animals and plants contribute to the water cycle, it's the respiratory activities of animals that directly return water to the air. In contrast, transpiration strictly involves plants. Other processes like evaporation, condensation, and sublimation involve water in the ecosystem but are different from respiration.