3.Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into playRequired to answer. Single choice.

The correct answer is - Friction occurs irrespective of the state of the matter.

Explanation:

Friction is the force that takes place when there are two different surfaces slide or moves across one another and causes a resistance between surfaces. The friction always takes place opposite direction to the other surface direction of moving.

Pushing a book on a table, pulling a heavy cart on road all are examples of friction. The friction that occurs in liquids and gases is called fluid friction. Thus, the friction takes place irrespective of the state of the matter.

i think the answer is

mass