The sea refers to a vast ocean or a large sea area. It is a natural landscape, which consists of a large number of water bodies, usually connected with land, but it may also be an isolated water body, containing different kinds of creatures, animals and plants. The sea is the largest water area on the earth, accounting for about 7 1% of the total area, and its depth and temperature are quite different. The sea has an important influence on economy, culture, ecology and climate.