Read the passage carefully and choose the correct answer.

EARTHQUAKES

How can scientists predict earthquakes? Earthquakes are not scattered anywhere but happen in certain areas, They happen in places where pieces of the earth’s surface meet. For example, earthquakes often occur on the west-coast of North and South America, around the Mediterranean Sea, and along the Pacific coast of Asia. Another way to predict earthquakes is to look for changes in the earth’s surface, like a sudden drop of water level in the ground. Some people say animals can predict earthquakes. Before earthquakes, people have seen chickens sitting in trees, fish jumping out of the water, snake leaving their holes and other animals acting strangely.

After an earthquake happens, people can die from lack of food, water and medical supplies. The amount of destruction caused by an earthquake depend on types of building, soil conditions and population. Of the 6000 earthquakes on the earth each year, only about fifteen cause great damage and many deaths.

Looking for ____  can help predict earthquakes.