There are different types of observers. Casual observers differ from scientific observer. Seeing and observing are two different things. Not that everybody seeing is actually observing the thing.
A casual observer just sits back and watch for something to happen while a scientific observer comes up with some hypothesis to work on it.
Females have two X chromosomes while males have one X and one Y chromosome
Answer:
C. Regulate how much carbon dioxide a country can emit
I think the correct answer is D