Select all that applyWhat can activate complement?Multiple select question.Pathogen surface moleculesMBL proteinPhagocytosis

The complement system can be activated by several factors. Here are the options that apply:

1. Pathogen surface molecules: Yes, these can activate the complement system. The complement system is part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane.

2. MBL protein: Yes, this can activate the complement system. Mannose-binding lectin (MBL) is a collectin that binds to sugar molecules on the surfaces of many pathogens and can trigger the lectin pathway of the complement system.

3. Phagocytosis: No, this does not activate the complement system. Phagocytosis is a process used by immune cells to engulf and destroy pathogens, but it does not directly activate the complement system. However, the products of the complement system can enhance phagocytosis, a process known as opsonization.