8.Why are forests good for the environment?
A. Forests make the environment cool.
B. Forests disrupt the ecological balance. C. Forests absorb excess amount of carbon dioxide in the air.
D. both A and C

9.What may happen if you increase the number of fish in an aquarium?
A. Organisms will get enough air.
B. Organisms will fight for survival.
C. Organisms will not compete for food. D. Organisms will not compete for space.

10.What kind of relationship may result if there are many animals than plants in the environment?
A. commensalism
C. mutualism
B. competition
D. parasitism​