Two students go to play basketball. They notice the ball is flat (it won't bounce). They decide to pump it up with air. a After it is pumped with air, will the ball have more, less, or the same amount of mass as before air was added?

b Cannot determine unless we measure the mass.

c The ball has more mass after being pumped with air.

d The ball has the same amount of mass after being pumped with air.

Justify your answer
The ball has less mass after being pumped with air.