Which deposition process delivers acids to ecosystems via precipitation?

• A. Wet deposition
• B. Dry deposition
• C. Adsorption
• D. Sedimentation

Answer: (A)

Wet deposition is the process by which acids are delivered to ecosystems through precipitation. When pollutants like sulfur dioxide and nitrogen oxides enter the atmosphere, they can react to form sulfuric and nitric acids. These acids dissolve in rain, snow, or fog and are deposited onto surfaces and bodies of water, lowering pH and harming ecosystems. Dry deposition, by contrast, brings pollutants down as gases or dry particles directly onto surfaces without precipitation. Adsorption is a surface-binding process, not a transport mechanism by precipitation, and sedimentation is the settling of particles out of the air or water, not the delivery of acids via precipitation.