Problem: Robert and his son Michael are going to the doctor for their yearly physical. Robert is currently in the late adulthood phase of his life. Michael, on the other hand, just began adulthood and is still quite young. Both of them want to ask the doctor about their risks for future health problems. Who is more likely to have a lower reflex time?

A: Michael

Problem: Two friends read about respiratory systems. Paul read more about the lungs of mammals, while Pete read more about the lungs of frogs. Which student read less about a network of very small blood vessels?

A: Pete

Problem: David is experimenting with electromagnetic waves. He has four different waves to study, wave A, wave B, wave C, and wave D. In wave A, distance between two corresponding points on adjacent waves is greater than that of wave B. In wave C, the number of waves that pass a fixed point in a given time is greater than that of wave D. Which wave has less energy, wave A or wave B?

A: wave A

Problem: Bill was studying the states of matter. First, he selected a matter with low boiling point. He labeled it as matter A. To compare it with a well-known matter he selected water. He labeled it as matter B. He also selected ice, which he labeled as matter C. He is now better prepared to compare their states. Would matter B have higher or lower density than matter C?

A:
higher