Describe greenhouse effect. [3 MARKS]
Each point: 1 Mark
1. A greenhouse is an enclosure of glass in which plants are kept to protect them from the cold air outside. The glass traps the heat of the sun, making the air inside warmer.
2. In a quite similar way, the carbon dioxide in the air traps the heat of the sun radiated back by the earth. This makes the air warm and comfortable for living beings, and in fact, makes it possible for life to exist on the earth.
3. But an excess increase in carbon dioxide has made much warmer than required and this is known as greenhouse effect.