It is called Gravity. For gravity is the force that causes our feet to stay on the ground. It was Newtons first universal law of gravitation.
"What goes up ...must come down."
Example : If I were to throw a rock up at the sky , It will come down in no time.
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Gravity is also what keeps the planets in our solar system , it's what keeps us in the suns gravitational pull.
I really hope that this helps
