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.
No, the vast majority of DNA mutations are not physically noticeable, and those that are noticeable physically are mainly cosmetic differences, such as a change in hair color, or heterochromia.
