This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Actin is made of: 
Select and explain. 
A. Polymerization of G actin, B. Myosin, C. F actine, D. All
A: Polymerization of G actin
Answer: A: Polymerization of G actin 
Explanation: Actin is made of polymerization of monomeric G proteins