C5a act as a/an?

Ans. is 'b' i.e., Chemotactic agent * C5a is a powerful chemotactic agent.* C3b, C3bi act as opsonin and enhance phagocytosis.* C5-9 Called membrane attack complex (MAC). It forms channel in the lipid membrane and causes cell lysis (including bacteria).* C5 is the point where both classical (antibody dependent) and alternative (antibody independent) pathways converge. Thus C5 forms the final common terminal pathway.