Substitutes are goods where you can consume one in place of the other.
Explanation:
The prices of complementary or substitute goods also shift the demand curve. When the price of a good that complements a good decreases, then the quantity demanded of one increases and the demand for the other increases.
Complementary goods are goods that are used together, and their demand patterns move in the same direction. Complementary goods are demand shifters because a complementary good will suffer a decline in demand, even without a change in its price, if the item that it complements has a price increase.
