This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
True about cytokines are all except: 
Select and explain. 
A. It is polypeptide, B. Have autocrine and paracrine effects, C. Involve in leukocytic movements, D. It takes pa in intrinsic enzymatic reaction
D: It takes pa in intrinsic enzymatic reaction
Answer: D: It takes pa in intrinsic enzymatic reaction 
Explanation: D i.e It takes pa in intrinsic enzymatic reaction They are polypeptideQ in nature.Induced their effect in three ways: Autocrine, paracrine & endocrine effects.Q Mediates natural immunity Affects leucocytic movementQRegulate lymphocytic growth activation & differentiation.Activate inflammatory cells & stimulate hematopoesis.