1. About _____% of the earth surface is covered by water.

• (a) 70%

• (b) 60%

• (c) 80%

2. The up and down movements seen on the surface of ocean water are known as ____ .

• (a) Tides

• (b) Ocean Currents

• (c) Waves

3. The _____ of the winds blowing over the ocean is the most important cause of the waves.

• (a) Pulling action

• (b) Pushing action

• (c) friction

4. Tides are caused mainly by _____.

• (a) attraction of the moon

• (b) gravitation of the earth

• (c) friction of winds

6. Which of the following is the source of fresh water?

• (a) Seas

• (b) Oceans

• (c) Snow and ice

10.The periodic rising and falling of sea waters.

• (a) Waves

• (b) Tides

• (C) Ocean Currents

11._____ occur when the sun, the moon and the earth are in a straight line.

• (a) Spring tides

• (b) Neap Tides

• (c) Bore Tides

12. ______ occur when the sun, the moon and the earth form three corners of a triangle, the attraction of the sun and Moon neutralize each other.

• (a) Bore Tides

• (b) Spring tides

• (c) Neap Tides