Explanation:

Statement 1 is correct: A wetland is a place where the land is covered by water, either salt, fresh or somewhere in between. They include mangroves, peat lands and marshes, rivers and lakes, deltas, floodplains and flooded forests, rice-fields, and even coral reefs. Wetlands exist in every country and in every climatic zone, from the Polar Regions to the tropics, and from high altitudes to dry regions.

Wetlands prevent flooding by holding water much like a sponge. By doing so,wetlands help Keep River levels normal and filter and purify the surface water.

Statement 2 is correct: Wetlands  also clean the water by filtering out sedimentation, decomposing vegetative matter and converting chemicals into useable form.

The ability of wetlands to recycle nutrients makes them critical in the overall functioning of earth. No other ecosystem is as productive, nor as unique in this conversion process. In some places artificial wetlands were developed solely for the purpose of water purification.

Statement 3 is correct: India has totally 67,429 wetlands, covering an area of about 4.1 million hectares [Ministry of Environment and Forests (MoEF), 1990]. Out of these, 2,175 are natural and 65,254, manmade. Wetlands in India (excluding rivers), account for 18.4% of the country’s geographic area, of which 70% is under paddy cultivation.