Final answer:
In economics, substitution is the ability to replace one resource with another when it becomes scarce or a better alternative is available. This is a common solution to demand and a long-term strategy to address shortages.
Step-by-step explanation:
In economics, substitution refers to the ability to replace one resource with another when the original resource becomes scarce or there is a better alternative available. This can be seen in the example of electronic books replacing traditional printed books due to their lower price and increased availability. A lower price for a substitute decreases demand for the other product. Similarly, a higher price for a substitute has the reverse effect. Substitution is a long-term solution to shortages and a common strategy to meet demand.