________ Is the force that causes objects with mass to attract one another
A. Speed
B. Momentum
C. Gravity

As the Average orbit of a planet, increases, the length of the year_____
A. Stays the same
B. Increases
C. decreases

What object, in our solar system governs the movement of the Celestial bodies in our solar system?
A. The planets
B. The moons
C. the sun ​

I really need help, thank you!