Explanation:

- The Ramsar Convention is an international treaty focusing on the conservation and sustainable use of wetlands.

- Its mission is to halt the encroachment and loss of wetlands now and in the future.

- Wetlands are crucial ecosystems that provide habitat for numerous species and help in water purification, flood control, and carbon sequestration.

- Option 1: Wetlands

- Correct Answer: The Ramsar Convention specifically aims to protect and conserve wetlands.

- Option 2: Rivers

- Although rivers are part of wetland ecosystems, the Ramsar Convention targets broader wetland conservation.

- Option 3: Oceans

- Oceans are not the primary focus of the Ramsar Convention, though they are also critical to global ecology.

- Option 4: Deserts

- Deserts are not the focus of the Ramsar Convention, which specifically concerns wetland areas.