talk about these ideas, too. 
 What happens when you start using a lot of pesticides? Read this story about the cats with parachutes to find out. 
 In Borneo in the 1950s, mosquitoes were giving people a disease called malaria. When people are ill with malaria they feel hot, then cold, and very tired; sometimes they even die. So the government used a lot of pesticide called DDT to kill the mosquitoes. Soon there was less malaria and that was a good thing. But then the grass roofs of people's houses started to fall on their heads. Why? Because caterpillars lived in the roofs and ate the grass. Before, wasps ate the caterpillars, but the DDT was killing the wasps, too. Now there was nothing to stop the caterpillars, and so the roofs started to fall down. Then there was a bigger problem. Cats