Question

The resistance which opposes the motion of moving parts is called ________________

Inertia
Gravity
Friction

Answer 1

The answer is friction. Friction is a force that causes moving objects to slow. Imagine you are trying to slide across a carpet. You can not slide across a carpet because of friction.

Answer 2

The resistance which opposes the motion of friction of moving parts is called friction.

Synonyms for Friction:  abrasion, abrading, rubbing.