Here's why:
* Gravity's Influence: Gravity is a fundamental force that attracts any two objects with mass. The Earth has a large mass, so it exerts a strong gravitational pull on everything around it, including water.
* Water's Response: Water is attracted to the Earth's center of mass, which is why it stays on the surface and doesn't float away into space.
* The Ocean's Shape: Gravity is also responsible for the shape of the oceans. The Earth's rotation and the gravitational pull of the Moon and Sun cause the oceans to bulge slightly at the equator and create tides.
So, gravity is the primary force that keeps Earth's water bound to the planet.
