All terrestrial planets may have the same basic type of structure; such as a central metallic core, mostly iron, with a surrounding silicate mantle. The Moon is similar, but has a much smaller iron core. Io and Europa are also satellites that have internal structures similar to that of terrestrial planets.
Average ACT: 33. The average ACT score composite at Stanford is a 33. The 25th percentile ACT score is 31, and the 75th percentile ACT score is 34. In other words, a 31 places you below average, while a 34 will move you up to above average. There's no absolute ACT requirement at Stanford, but they really want to see at least a 31 to have a chance at being considered.
The Class of 2018 Stanford admitted only 9% of the applicants with 800 on their math SAT. Yet 25% of the entering students had math SAT scores below 700. There were a few admits who had math scores below 600. If academics were the only criteria, virtually everyone at Stanford would have at least 750 on the math SAT.