Introduction


INTRODUCTION


•      The two most important things without which we won't be able to live are air and water.

•      The air is all around us in our environment, and we take it in when we breathe.

Figure 1: Use of water in various ways

•      This air consists primarily of oxygen and nitrogen in addition to small amounts of other gases, bacteria, and viruses.

•      Water is important to us in many ways.

•      It is used for:

       1. Bathing, 2. Drinking, 3. Washing, 4. Cleaning, 5. Cooking, 6. Watering plants