Identify the correct statement from the following :

1. Mass is a force and is measured in Newton.
2. The weight of a body is the same everywhere in the universe.
3. Mass remains constant, but weight changes with gravity.
4. Weight is measured using a physical balance.

Mass remains constant, but weight changes with gravity.

Reason — Mass is the amount of matter in a body so it does not change regardless of location but weight is the force with which a body is attracted towards the Earth (or any other celestial body), and it depends on gravity and is given by :

$\text {Weight (W)} = \text {Mass (m)} \times \text {Acceleration due to gravity (g)}$

So, weight changes when gravity (g) changes (e.g., on the Moon, where gravity is less, weight is less).