Marine biology is the study of the ocean’s plant and animal life. Marine life gives us food, medicine and other raw materials we need. It also supports tourism and provides us with an area of recreation.

    1     (difference)forms of life live in various areas of the ocean. Some are limited to coastal and shelf areas, while others live in the open sea.

Coral reefs     2     (find) in the tropical areas of the world, but they can also exist in colder water. Reefs are built by corals and other     3     (animal)that leave calcium on rocks. They are home to     4     vast variety of life forms. About half of the world’s coral reefs, however,are     5     danger because of global warming and a rise in sea temperatures.

Although we do not know very much about    6     kind of life forms exist in deep ocean trenches(深海沟), marine scientists have found a certain type of jellyfish(水母) in the Mariana Trench, the world’s     7     (deep)ocean area. These parts of the ocean     8     (usual)have little or no sunlight and many organisms(生物)here have to produce light     9     (they).

Marine scientists also study how waves and currents affect organisms     10     (live)in the oceans.