👉 "Opsonia" is a term used in marine biology and biochemistry to describe a type of protein that binds to other proteins, such as antibodies or phagocytosis receptors. It refers to an enzyme that catalyzes the binding of an antibody to another molecule, allowing the antibody to be released from the cell and its ability to bind with other molecules. In simple terms, opsonia is a type of protein that helps cells like bacteria and viruses kill each other by attaching to