Answer: substitute goods
complementary goods
Explanation: Substitute goods refers to the goods which could be used at each others place. For example - coke and Pepsi. Complementary goods are the goods which are used together. For example- Petrol and petrol car.
When the price of a good decreases the demand for its substitute decreases while for its complementary goods there comes an increase in demand.
Hence from the above we can conclude that beef and chicken are substitute goods, while beef and french fries are complementary goods.
