Seagulls living on the coast can rely on drinking sea water to replenish their body's moisture. In 1950, American scientist DR.S. Sourirajan observed the seagulls and found that the seagulls would pick up a large amount of sea water as they swept across the sea. After a few seconds, they spit out a small amount of sea water. He was very confused because the animals that landed by the lungs were absolutely unable to drink seawater with high salinity. After the anatomy of the seagull, the seagull did not directly drink the seawater, but the seawater was in the throat. The structure of the seagull pipe was composed of layers of mucosal tissue. The seawater was inhaled through the seagull and pressurized. Then, through the action of pressure, the water molecules are transformed into the fresh water through the permeation mucosa. The seagull absorbs the fresh water filtered by the mucous membrane into the body, and then spits out the remaining high-concentration seawater. The reason why the seagull can drink the secret of the seawater is it's here. This is the basic theoretical framework of the reverse osmosis method.