31. Which of the following activities describes change in material that is useful in the environment?
A. cutting trees
C. throwing of garbage in the river B. making basket using rattan
D. burning of substances in the factory 32. Which of these activities is useful to the environment?
A. planting trees
C. throwing trashes in the river
B. burning trashes
D. burring substances in the factory
33. The following actions are examples of changes in the materials which are useful to the environment, EXCEPT:
A. using both sides of bond paper when writing
B. using old newspaper in wrapping gifts C. using pesticides in killing insects
D. using eco bags when buying groceries 34. Dexie's father sliced up rubber tires to use as planters for their decor plants. What does this situation demonstrates? A. Both physical and chemical change happened.
B. Neither physical nor chemical change happened.
C. Physical change happened.
D. Chemical change happened.
answer plsss​