<prompt> Ferritin biosynthesis is regulated by serum level of ?CeruloplasminHepcidinIronTransferrin  <response>: Ans. is c i.e., IronThe level of iron in plasma is sensed by specific iron regulatory proteins which control the rate offerritin synthesis and to maintain homeostasis - Human physiologyHepicidin regulates absorption of iron. But, it is also according to the serum iron level. If serum iron is deficiem, hepacidin level falls and there is increased iron absorption. 