When the Martian axis tilt is small, the Martian poles
A) expand and remain permanently frozen, thinning the atmosphere
B) contract and partially vaporize, thickening the atmosphere
C) extend over the entire surface of the planet
D) completely disappear

Question

Quizplus · Accepted Answer

When the Martian axis tilt is small, the Martian poles expand and remain permanently frozen, thinning the atmosphere. This is because the polar ice caps contain a significant amount of carbon dioxide, which is a greenhouse gas. When the poles expand and remain frozen, the carbon dioxide is removed from the atmosphere and causes it to thin.

When the Martian Axis Tilt Is Small, the Martian Poles