Here's a breakdown:
* Thin Atmosphere: Mars' atmosphere is about 100 times thinner than Earth's. It's primarily composed of carbon dioxide (95.3%), with small amounts of nitrogen (2.7%), argon (1.6%), and trace amounts of other gases.
* Low Atmospheric Pressure: The pressure at the surface of Mars is only about 0.6% of Earth's, similar to the pressure found at an altitude of 35 km (22 miles) on Earth. This means Mars' atmosphere is much less dense than Earth's.
* No Liquid Water: The thin atmosphere and low pressure prevent liquid water from existing on the surface of Mars, although there is evidence of past water activity.
Therefore, the correct answer is that Mars has a thin atmosphere. It's not heavy like Earth's, but it's not nonexistent either.
