For water to have been stable on Mars in the past,
A) temperature must have been higher and the atmospheric pressure lower
B) temperature must have been lower and the atmospheric pressure higher
C) both the temperature and the atmospheric pressure must have been higher
D) both the temperature and the atmospheric pressure must have been lower

Question

Quizplus · Accepted Answer

For water to have been stable on Mars in the past, both the temperature and the atmospheric pressure must have been higher. Higher temperatures would prevent water from freezing, and higher atmospheric pressure would prevent it from evaporating too quickly, allowing liquid water to exist on the surface.

For Water to Have Been Stable on Mars in the Past