When complement proteins coat a pathogen and this coating enhances its engulfment by phagocytic cells, the process is given a specific name. What is it?

1. Complement proteins bind to the surfaces of microorganisms and are especially attracted to pathogens already bound by antibodies. 2. These proteins mark the pathogen for phagocytic cells, such as macrophages and B cells, enhancing engulfment. 3. This marking process is called opsonization. 4. Apoptosis is programmed cell death, extravasation is immune cells passing into surrounding tissue, and phosphorylation is a chemical modification, none of which names this marking-for-engulfment process. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 42 "The Immune System", section Complement_