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

Elements are pure substances that make up all matter.
Elements are pure substances that make up what?

In the tropics tradewinds are the prevailing winds called.
In the tropics what are the prevailing winds called?

The effect of acetylcholine in heart muscle is inhibitory rather than excitatory.
The effect of acetylcholine in heart muscle is inhibitory rather than what?