17. The following are effects in the environment by the changes in matter. Which of these has a good effect on the environment?
A. air pollution
B. composting
C. deforestation
D. water pollution

18. Many families use wood as fuel in cooking food. What is the bad effect on the
environment of this activity?
A. deforestation
B. air pollution
C. land pollution
D. water pollution

19. The following activities can be done to candy wrappers. Which of these can help
protect and save the environment?
A. throw garbage into the river
B. scatter candy wrappers in the backyard
C. cut out candy wrappers to make pillows
D. burn candy wrappers because these are biodegradable wastes

20. Water pollution is one of the bad effects in the environment by the changes in matter.
Which of the following can minimize bad effects in the bodies of water?
A. oil spills from a cargo ship
B. bringing trash bins when having a picnic in the beach
C. throwing detergents and other chemicals in the river
D. using bath soap and shampoo in swimming at the beach

21. Why are some waste in other places left uncollected?
A. Our landfills have a lot of space for our wastes.
B. Our landfills cannot accommodate all our wastes.
C. Our collected waste products are fewer everyday.
D. Our garbage collectors in our place are few.
22. What will happen to uncollected waste?
A. It can produce waste.​