What do you hear a sound when you crack your knuckles

your joints, stretch the joint capsule. Gas is rapidly released, which forms bubbles.

Explanation:

The best substitution that can help in reducing air pollution is option A. using a bike instead of a car. It is known that vehicle emission is the top reason of the worsening case of air pollution. These emissions consist of nitrogen oxides and carbon monoxide which can cause several respiratory health problems.