Answer:
The Bowling Ball is Denser.
Explanation:
If we consider both balls in terms of mass they are very different. Size and volume can be the same though.
What makes the mass? Think of what fills each of the balls.
A Basketball is filled with air, which weighs very little.
Meanwhile, a bowling ball is filled with coverstock, made up of plastic, urethane and resin. These materials weigh considerably more than air!
