17. According to scientific evidence, which event would have been the first to occur during the formation of the Solar Systern? A collapsing cloud of gas and dust formed accretion disk around the young Sun.
A Mars-sized object collided with Earth, which led to the formation of the Moon.
A period of heavy bombardment of meteorites merged together to form the inner planets.
A cooling period occurred, which allowed for rocks on the new planets to harden.