In a vacuum, all bodies fall with the acceleration of gravity. why in the air a piece of cotton wool

In a vacuum, all bodies fall with the acceleration of gravity. why in the air a piece of cotton wool falls with less acceleration than the rest of the ball?

In air (liquid), when an arbitrary body moves, a resistance force arises. This force depends on the properties of the medium (for a piece of cotton wool and a steel ball, they are the same (air)); the shape, size of the body (a piece of cotton wool will have larger dimensions due to its lower density) and surface condition (the roughness of the surface of a piece of cotton wool is much larger).

Consequently, due to the large size and greater surface roughness, a piece of cotton wool will experience a greater resistance force and fall with less acceleration.