Explanation:

A wetland is a place where the land is covered by water. Marshes, ponds, the edge of a lake/ocean, the delta at the mouth of a river, low-lying areas that frequently flood — all of these are wetlands.

• As per the Ramsar Convention definition most of the natural water bodies (such as rivers, lakes, coastal lagoons, mangroves, peatland, coral reefs) and man made wetlands (such as ponds, farm ponds, irrigated fields, sacred groves, salt pans, reservoirs, gravel pits, sewage farms and canals) in India constitute the wetland ecosystem.
• Wetlands are indispensable for the countless benefits or ?ecosystem services? that they provide humanity, ranging from freshwater supply, breeding and nesting areas for birds and animals, food and building materials, to control flood by protecting the coastlines from erosion as well as reducing the damage from cyclones, groundwater recharge, purifying water and climate change mitigation etc.
• Hence all the statements are correct.