The Carbon Dioxide Atmosphere of Mars Was Much Denser in Mars's

Multiple Choice

The carbon dioxide atmosphere of Mars was much denser in Mars's early history than it is now.What process is now believed to have begun this atmospheric thinning?

A) The solar wind stripped the outer atmosphere from the planet.
B) The light CO₂ molecules escaped directly into space because of the weak gravity of Mars.
C) The CO₂ molecules were broken down by solar UV photons,creating the lighter molecules,CO and O₂,which then escaped into space.
D) The CO₂ was washed out of the atmosphere by rain.