Final answer:
The correct answer is (C) The billiard ball will sink deeper due to its density because the tennis ball, being less dense than water, will float, whereas the denser billiard ball will sink.
Step-by-step explanation:
The question relates to the principles of density and buoyancy in physics, particularly Archimedes' principle, which dictates that the upward buoyant force exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces.
Given that a tennis ball is filled with air compared to a solid billiard ball, we can deduce that their densities are different despite having the same volume. The density of a substance is given by the mass per unit volume. Since the tennis ball is filled with air, it is less dense than water, while the billiard ball, being solid, is likely denser than water.
Therefore, when placed in water, the tennis ball will float on the surface due to its lower density compared to water, while the billiard ball will sink deeper in the water due to its higher density. So, the correct answer is (C) The billiard ball will sink deeper due to its density.