The Oceans

Oceans play a major role in the earth’s natural processes because of their production and control of climate, supplying moisture to the atmosphere and providing a vast climatic regulator. They form the ultimate site of deposition of almost all sediment and are the home of many living species of animals and plants. The oceans cover over 70 percent of the earth’s surface. The continents are surrounded by shallow, gently sloping continental shelves. The average ocean depth is almost three miles, but trenches, up to 36,000 feet deep, are found in places. Although much of the deep ocean floor is a flat plain, some parts are more mountainous than the mountain regions of dry land. A worldwide system of midoceanic ridges includes submarine mountain chains, marked by intense vulcanism and earthquake activity, and offset by transform faults. They are the sites of the formation of new crustal rocks. There are also many volcanic islands, including many submerged below sea level.

Statements:

1. Earth’s natural processes are greatly affected by oceans.
2. Moisture controls the climate of the earth.
3. Oceans are the home of many living species.
4. There is no life in ocean shelves.
5. Shelves are very deep.
6. The average ocean depth is almost 36,000 feet deep.
7. Some parts of the ocean are more mountainous than the dry land.

Exercise 5. Read the following texts and match them with the titles given below: