C3a, C5a are called?

Ans. is 'd' i.e., Anaphylotoxins * C5a, C3a 8c to a lesser extent C4a- are called anaphylotoxin because they have effects similar to those of mast cell mediators that are involved in the reaction called anaphylaxis. These effects are due to stimulation of histamine release by these anaphylotoxin. The effects are increased vascular permeability and vasodilatation.