Final answer:
In order to sing a valid contract, a person must have legal capacity and consent.
Step-by-step explanation:
In order for a person to sing a valid contract, two characteristics are required: legal capacity and consent.
Legal capacity means that the person must have the mental capacity to understand the terms of the contract and the consequences of entering into it. For example, minors may lack legal capacity to enter into certain contracts.
Consent means that the person must voluntarily agree to be bound by the terms of the contract. If consent is obtained through fraud, coercion, or mistake, the contract may be voidable.