Here's why:

* Gravity: Gravity is the force pulling the object downwards.

* Air Resistance: As the object falls, it encounters air molecules. These collisions create a force that opposes the object's motion, acting in the opposite direction of gravity.

Factors affecting air resistance:

* Speed: The faster the object falls, the greater the air resistance.

* Shape: Objects with larger surface areas experience more air resistance.

* Surface Texture: Rough surfaces create more air resistance than smooth ones.

Terminal Velocity: Eventually, the force of air resistance becomes equal to the force of gravity. At this point, the object stops accelerating and falls at a constant speed called terminal velocity.