A contract must include the exchange of something of value, which is also known as:

The correct answer is "consideration," which refers to something of value that is exchanged between parties in a contract. In the context of contract law, consideration is a fundamental element because it represents the incentive for both parties to enter into the agreement. It can take various forms, such as money, services, or goods, and is essential for the contract to be enforceable. Without consideration, a contract is typically not binding, as there would be no reciprocal obligation or benefit for the parties involved.

Other elements of contracts, such as legality, capacity, and mutual agreement, are also important in ensuring that a contract is valid and enforceable. Legality requires that the contract's subject matter be lawful, capacity ensures that all parties involved have the legal ability to enter into the contract (such as being of legal age and mentally competent), and mutual agreement refers to the need for all parties to consent to the terms of the contract. However, it is consideration that specifically addresses the exchange of value necessary to form the contract itself.