What do we call the quantity of matter that an object contains?
a. mass
b. weight
c. volume
d. density

The correct answer to the question is A). Mass i.e the quantity of matter that an object contains is mass.

EXPLANATION:

The mass and weight are two different physical quantities of a body.

The weight of a body is the force with which a body is attracted towards the centre of earth. Hence, it is vector quantity.

Mathematically, it is the product of mass of the body with acceleration due to gravity.

 It is written as W = mg.

In comparison to weight, the mass of a body is a scalar quantity.

The mass of a body is defined as the amount of matter that is contained by a body irrespective of volume or any forces acting on it.

For non-relativistic situation, the mass of a body is always constant. It is unaffected by gravity also.

For relativistic phenomenon, the mass of a body is appeared to be increasing when a body moves with a velocity compared to velocity of light.