Physiology General b3071c80 Curdling of milk is caused by - A Rennin B Lipase C Amylase D Elastase High-Yield Explanation Ans. is'a'i.e., Rennin [Ref: Concise oxford dictionary p. 1218iRennin is an enzyme secreted into the stomach of unweaned mammis causing the curdling of milk.