Questions: Listen The inner planets are made mostly of rock and metal because... the Sun is made mostly of rock and metal and the inner planets are closest to the Sun lighter materials cannot orbit the Sun; they would fall in immediately it was so hot where the inner planets formed that the lighter materials evaporated Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form

The answer is the third one: it was so hot where the inner planets formed that the lighter materials evaporated.

Explanation for each option:

1. The Sun is made mostly of rock and metal and the inner planets are closest to the Sun: This is incorrect. The Sun is primarily composed of hydrogen and helium, not rock and metal. The composition of the Sun does not directly determine the composition of the planets.

2. Lighter materials cannot orbit the Sun; they would fall in immediately: This is incorrect. Lighter materials can and do orbit the Sun. The presence of lighter materials in the outer planets, which are composed largely of gases like hydrogen and helium, demonstrates that lighter materials can remain in orbit.

3. It was so hot where the inner planets formed that the lighter materials evaporated: This is correct. The inner planets formed in the hotter region of the solar nebula, where temperatures were high enough to prevent volatile compounds like water, methane, and ammonia from condensing. As a result, these lighter materials were not incorporated into the inner planets, which are primarily composed of heavier elements like rock and metal.

4. Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form: This is partially correct but not the primary reason. While Jupiter's gravity did influence the distribution of materials in the solar system, the primary reason for the composition of the inner planets is the temperature gradient in the early solar system, which caused lighter materials to evaporate in the inner regions.

In summary, the inner planets are made mostly of rock and metal because the high temperatures in the region where they formed caused lighter materials to evaporate.