The force that pulls everything on Earth down is gravity. Gravity is a fundamental force of nature that causes objects with mass to be attracted to each other. It is what keeps us grounded on the Earth and gives weight to objects. Without gravity, things would float off into space.
Gravity is responsible for the phenomenon of things falling when dropped. For example, if you drop a ball from a height, it falls to the ground due to the force of gravity pulling it downward.
In contrast, the other options provided in the question - motion, friction, and speed - do not represent the force that pulls everything down on Earth. While motion and speed are related to the movement of objects, they do not specifically refer to the force of gravity. Friction, on the other hand, is a force that opposes motion but is not the force responsible for pulling everything down towards the Earth.
