Answer: Create a model.
Explanation: He should develop a model of the Earth-Moon-Sun system. This will let him clearly see how the Moon must move in order for one of its sides to always face away from the Earth. If he uses a light source for the Sun in his model, it will also show how the phases of the Moon happen. The real Earth-Moon-Sun system is too large for him to observe it in the same way.
A. Foil
This is because he is the opposite character of Romeo.
