17. The earth pulls upon all objects and holds them because of its great mass. This strong pullis known as gravity and is in the direction of the earth's center Gravity holds the ocean waters in their bedis the plants in the soil, and the animals on their feet on the ground. Anything thrown into the air is pulled back to the ground by gravity Gravity also keeps the earth's atmosphere from dnting off into space a. The earth's gravity is strong b. Gravity pulls and holds all things on earth. cGravity is like paste, d Nobody and nothing can fall off the earth​