Why is the sea blue?

The real reason why seawater is blue lies in the reflection and absorption between light and seawater. What we see is the color of blue light and purple light left after being scattered by seawater. Because the human eye is not as sensitive to purple as blue, the ocean we see appears blue.

Ocean:

Sea, a geographical term, is the floorboard of the widest water body on the earth. The earth's surface is divided into huge interconnected water bodies by the mainland, which are called oceans. The central part of the ocean is called ocean, and the marginal part is called sea. They communicate with each other and form a unified water body. The total ocean area on the earth is about 360 million square kilometers, accounting for 7 1% of the earth's surface area, with an average water depth of about 3795 meters. The ocean contains more than1350 million cubic kilometers of water, accounting for about 97% of the total water of the earth, and only 2% is available for human consumption.