1. Compare and contrast the surface appearance (i.e., at ground level) of the planets and moons in the inner part of the solar system. Explain why these surfaces appear as they do today.

2. Compare and contrast the atmospheres of the four inner solar system planets, and summarize the likely evolution of the atmosphere of each of those planets, beginning with planet formation and ending with the present.

3. Explain why we believe life on the surface of Earth could not evolve until the atmosphere contained free oxygen. What present-day practices threaten to negate the unique feature of our atmosphere that permits land-based life (if you answer with global warming, may a storm cloud immediately descend on your home)?