Goods and/or services that are often consumed together; e.g., left and right socks, or tennis rackets and tennis lessons. View Capstone Lesson(s) that address this concept

If goods X and Y are complements, the quantity demanded of X is inversely related to the price of Y

are goods that are used in conjunction with other goods.

Eleven specific enzymatic proteins occurring in normal serum which interact and destroy foreign cellular bodies.

A price change for one product leads to a shift in the opposite direction direction in the demand for another product.