Here's why:

* Gravity is a fundamental force: It's one of the four fundamental forces of nature, alongside electromagnetism, the strong nuclear force, and the weak nuclear force.

* Mass creates gravity: The more mass an object has, the stronger its gravitational pull.

* Everything has mass: Even tiny particles like atoms have mass.

Why some objects seem to have no gravity:

* Small mass: Objects with very small mass, like a grain of sand, have an incredibly weak gravitational pull that's almost impossible to detect.

* Distance: Gravity weakens with distance. So, even if an object has a significant mass, its gravitational pull on you will be very small if you're far away from it.

Example:

You might think a feather doesn't have gravity because it's so light, but it does! It's just that its gravitational pull is so small it's insignificant compared to the Earth's much larger gravitational force.