How do the planets earth and mercury compare with respect to atmospheres? a. mercury's atmosphere has more nitrogen than earth's. b. their atmospheres are identical. c. mercury's atmosphere is much thinner and less dense than earth's. d. earth's atmosphere is much thinner and less dense than mercury's. reset submit

The atmosphere of Mercury is so thin that it can be said that it lacks of atmsphere. Therefore, it has no way to retain the heat from the Sun. This means all the heat the planet receives and that is reflected, radiates to the space, unlike the Earth that has a very dense atmosphere in comparison with Mercury, having part of the received heat absorbed before being radiated to outer space.

Another important consequence of this  lack of a viable atmosphere in Mercury, is that its surface is very similar to the Moon, a world with extremely high temperatures during the day and low freezing temperatures at night.