Question 1
Early Earth was hot because ________.
◦ the Sun was much larger and heated the early planet
◦ a combination of collisions and radioactive decay produced heat
◦ there was still heat from the original big bang
◦ the moon's formation from an giant impact produced heat
◦ gravitational collapse generates heat
Question 2
Earth's core, mantle, and crust formed during the ________.
◦ Hadean
◦ Archaean
◦ Proterozoic
◦ Tertiary
◦ Paleozoic