Water is necessary for life. People can live only a few days (1) it. Yet nearly 25 million people die each year because of it. Both industrial nations and less-developed countries are worried about the (2) and quantity of water in the world.

Even though people, animals, agriculture, and industry use a lot of water, there is more than enough on the Earth. Water covers about three-fourths of the Earth's surface. However, 97.4 percent of it is salt water. Three-fourths of the Earth's fresh water is frozen in glaciers and in the great polar ice caps. Most of the water we use (3) from rivers, lakes, and the atmosphere. Less than one percent of the Earth's water is usable, and we use it over and over again.

One of the (4) about water is distribution. Water is not always distributed where the large (5) centers are. Some regions get enough rain, but it is all in one or two short rainy seasons.