glass II. Directions: Circle the letter of the correct answer. 6. It refers to the process where the substance bums in the presence of oxygen. a. Rusting b) Combustion c. Oxidation d. Humidity 7. What is the caused by reaction of iron with oxygen present in the alr? a. Humidity b. Moisture @ Rusting d. combustion 8. The following are the ways to prevent rusting, except one. a. Keep it clean and dry. b. Apply paint Let it wet and moist. d. None of the above 9. What wll happen if one element needed for combustion is not present? a. The fire will continue its flame. Q Combustion will not occur. c. There should be heat, fuel and oxygen. 10. Which of the following shows the absence of oxygen in a material? a. combustion Lighted candle covered with glass c. Rusting 11. Which of the following shows the proper way to recycle. a. Scrap papers from the classroom might be turned into paper bags. b. Buy items in refillable containers. c. Use cloth bags or baskets when you buy groceries/market. d. Use both sides of paper in printing. 12. Plastic is commonly used as soft drinks container, what material can you use as a substitute for plastic? a. empty cans c. used cups b. empty bottles d. folded papers 13. In his class, Mr. Ibarra told his pupils to reuse papers instead of throwing it in the bin.How will they do it? a. Make an origami. c. Give to your classmate. b. Use it as scrap paper in math. d. Never mind the advice of the teacher. 14. Some materials are normally useful even after serving its original purpose. What wil you do to an empty canister at home? a. Place it inside the cabinet. c. Burn it. b. Use it as a lunch box. d. Make a trash bin out of it 15. The following materials can be reused, EXCEPT. b. paper C, aluminium cans d. paint brus a. woods​