Here's why:

* Pulls on objects: Gravity attracts objects with mass towards each other. The more massive an object, the stronger its gravitational pull.

* Causes acceleration: When an object is subject to gravity, it accelerates towards the center of the mass that is attracting it. For example, objects fall to the ground because of Earth's gravitational pull.

* Unbalanced forces: If the only force acting on an object is gravity, it will accelerate. However, if there are other forces acting on the object (like air resistance or a supporting surface), these forces can balance out gravity and prevent acceleration.

Let me know if you have any other questions!