The differences between Earth's and Venus' atmospheres.
Venus and Earth are about the same size and mass, yet carbon dioxide is a major constituent of the atmosphere of Venus, while oxygen is much more abundant in the Earth's atmosphere. Explain why the atmospheres are so different.
The formation is atmospheres is emphasized. - This job considers how atmospheres form. Given that Venus, Earth, and Mars are all terrestrial planets, the posting briefly discusses how they could end up with such different atmospheres.