Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

A bow wake is created when the wave source moves faster than the wave propagation speed.
What is created when the wave source moves faster than the wave propagation speed?

Antifreeze lowers it the freezing temperature of the water in car radiators.
What does antifreeze do to the freezing temperature of the water in car radiators?

Regular changes in biology or behavior that occur in a 24 hour cycle are part of the circadian rhythm.

What are regular changes in biology or behavior that occur in a 24 hour cycle?