In Standard Five, you learnt about the main characteristics of living things including breathing. You learnt that plants and animals need air for their survival. Animals use oxygen for respiration and give out carbondioxide.Duringphotosynthesis,plantsusecarbondioxideand give out oxygen. In this chapter, you will learn the concept of air and characteristics of gases that compose air. You will also learn about the use of air in daily life. The knowledge and skills acquired through this chapter will help you to conserve the environment and hence increase fresh air and also reduce production of dangerous gases.