Gravity causes objects that have mass to be pulled down on a planet.
Astronomy is the scientific study of the stars, planets and the other celestial bodies.
Gravity pulls down objects that have mass on a celestial body.
What causes objects to be pulled down on a celestial body?
(1) power
(2) friction
(3) black hole
(4) wind
(5) gravity
(6) orbit
(7) earth
(8) eclipse