Based on the Nebular theory, which of these best describes how the center of a new planetary system is formed?
by the merging of atoms
by the splitting up of atoms
by the rotation of the moons of the planets
by the gravitational pull of the moons of the planets
by the merging of atoms
by the splitting up of atoms
by the rotation of the moons of the planets
by the gravitational pull of the moons of the planets