Final answer:
Gravity's role in solar system formation was to cause the nebula to collapse and separate material into individual celestial bodies, influencing orbital dynamics and assisting in the coalescence of planets and other celestial objects.
Step-by-step explanation:
The role of gravity in the formation of the solar system was fundamental. The correct answer to the student's question is A. Gravity caused the solar system to separate into individual celestial bodies. Our solar system was formed roughly 4.5 billion years ago from a solar nebula, a rotating cloud of gas and dust. As the nebula collapsed under its own gravity, material fell toward the center where the Sun formed, and the remaining disk of material coalesced into planetesimals, which eventually grew into the planets. The gravitational pull of these forming bodies caused them to attract more material and become differentiated into a central star, planets, and other celestial bodies. Additionally, gravity influenced the orbits and spins of these planets to conserve the angular momentum of the original solar nebula.
The gravitational effects of Jupiter and Saturn played a significant role in the redistribution of asteroids and influenced the history of the solar system. The gravitational interaction between these giant planets and planetesimals could have led to an inward migration of Jupiter's orbit and an expansion of the orbits of Saturn, Uranus, and Neptune, along with the Kuiper belt. Moreover, gravity permits the calculation of the masses of astronomical objects and the prediction of their movements and interactions.