A block of wood and a block of metal are both placed in water. The wood floats while the metal sinks. What can be concluded about their densities?

• A. Both the wood and the metal have lower densities than water.
• B. The wood has a higher density than water, and the metal has a lower density than water.
• C. Both the wood and the metal have higher densities than water.
• D. The wood has a lower density than water, and the metal has a higher density than water.

Answer: (D)