Final answer:
Soybeans are complete proteins containing all nine essential amino acids, unlike other legumes like red beans, which are high in protein and fiber but not complete proteins.
Step-by-step explanation:
Soybeans are complete proteins. They differ from other plant proteins because they are a source of all nine essential amino acids that the human body cannot produce on its own. Other legumes, like red beans, are not complete proteins but are high in protein and high in fiber, which makes them an important part of a balanced diet. Complete proteins such as soybeans are vital for maintaining good health as they provide the building blocks for various body structures including muscles and enzymes that facilitate biochemical reactions.