Why is the atmosphere on Mars a solution?

I gotta call BS on this question. Mars has a thin atmosphere (6 millibars - less than 1% of Earth's) which is primarily carbon dioxide (95.3%) iwth trace amounts of nitrogen (2.7%), argon (1.6%) and other trace gases (0.4%). The atmosphere of Mars appears pink because of the fine particles of iron oxide that are suspended in it. If anything, you could call the atmosphere a suspension.