Answer: D
Reasoning: If you think about it you cannot use it's in any other tense. Past tense, it's wouldn't work. Future tense, it's may not work.
Tactic: Process of Elimination
The answer is A. It shows that animals depend on this process for oxygen.
Photosynthesis is how Carbon dioxide (what we breathe out) is turned into Oxygen (what we breathe in)
If Photosynthesis never took place Oxygen would run out and animals would suffocate.
With the theme being the rules of society do not always benefit the needs of an individual the setting for this would be when Shear Khan is trying to kill Mogli in the jungle. I hope this helps.
