2.
The inertia of an object depends on its

Inertia of an object depends on the mass of the object.

Explanation:

Inertia is the property that is possessed by a matter( anything that has weight and occupies space) that enables it to be at rest or in a state of continuous uniform motion.

The inertial of a body is the resistance that is present in the body, that forces acting on the body have to overcome for the body to move or continue moving.

The inertia of a body depends on the mass of such a body, which is directly proportional. The mass of an object is the measure of inertia,  the bigger the mass of an object the bigger the inertia.

Therefore the Inertia of an object is largely dependent on the mass of such an object.