Learning Task No. 4. : Identify the following changes that will happen in the materials in each activity or situation. Tell whether they are use- ful or harmful in the environment. Write the correct answer in the proper column. 1. Cutting of trees 2. Shaping of wood to make furni- ture 3. Hammering/shaping iron to make bolo 4. Burning of old tires 5. Shredding paper for paper mache 6. Cooking of food 7. Throwing detergents into the sewage 8. Killing animals in the forest 9. Sewing fabric to make clothes 10. Dumping garbage into the river Harmful Useful​