Nobody's is the correct spelling
Having complete and total awareness, understanding, or knowledge, as in an omniscient narrator is the correct answer.
I agree with the person above - I'd say the correct answer is B. The greenhouse effect is changing Earth's atmosphere.
A is incorrect because the excerpt says that the atmosphere keeps the Sun's heat from leaking away into space. C is incorrect because it is the greenhouse effect that keeps the planet warm. D is not even mentioned in the text, which means that only B is correct.
By adding a subject and a verb is the answer
