The Fc piece of which immunoglobulin fixes complement 1 -
High-Yield Explanation
Ans. is 'c' > 'b' i.e., IgM > IgG o Make it very clear in your mind that both IgM and IgG fix C1." CH2 of IgG and CH4 of IgM bind to C1q portion of C1"-------Ananthanarayan" Clq portion of Cl is an aggregate of 18 polypeptides that binds to the Fc portion of IgM and IgG"--LANGE microbiologyo However, if you will have to choose one option, IgM is the best because IgM is more effective than IgG for complement fixation.