Final answer:
A complete protein is one that contains all nine essential amino acids in sufficient quantity and ratio. Animal proteins are good examples of complete proteins, while most plant foods are incomplete proteins.
Step-by-step explanation:
A complete protein is one that contains all nine essential amino acids in sufficient quantity and ratio for the body's needs.
Animal proteins such as meat, fish, milk, and eggs are good examples of complete proteins, while most plant foods are incomplete proteins.
Incomplete proteins do not contain adequate amounts of one or more of the essential amino acids.