A. Directions: Draw a happy face ( Ⓡ ) if the following statements show useful changes in the materials in the environment, and a sad face () if the changes brought in the materials are harmful to one's environment. 1. burning of tires 2. growing of new trees 3. increase in soil fertility 4. increase in food production 5. cutting fabric made into clothes 6. cutting of cloth made into handkerchief 7. empty plastic bottles dumped into rivers​