Scientists believe that the [answer] explain why Earth’s [answer] fluctuated between glacial periods and interglacial periods.

Question

Scientists believe that the [answer] explain why Earth’s [answer] fluctuated between glacial periods and interglacial periods.

possible answers for question 1: [low temperatures, tilt of Earth's axis, Milankovitch cycles, sea levels]

possible answers for question 2: [climate has, sea levels have, tilt of Earth's axis, low temperatures have]

Answer 1

Scientists believe that the [answer] explain why Earth’s [answer] fluctuated between glacial periods and interglacial periods.

Scientists believe that the Milankovitch cycles explain why Earth’s tilt of Earth's axis fluctuated between glacial periods and interglacial periods.