Question

1. what is the force that keeps the planets moving around the sun and keeps the planets round?

Explanation:

This force acts as the centripetal force that maintains planets' orbital motion around the Sun by pulling them toward the Sun, preventing them from moving in a straight line. It also pulls all the mass of a planet inward equally from all directions, shaping the planet into a spherical (round) form as gravity pulls matter toward the planet's center of mass.

Answer:

Gravitational force (or gravity)