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
Fluidity of the membrane is maintained by: 
Select and explain. 
A. Cholesterol, B. Carbohydrates, C. Proteins, D. All
A: Cholesterol
Answer: A: Cholesterol 
Explanation: Cholesterol maintainds the fluidity of the membrane Poly unsaturated fatty acids increase fluidity Saturated fatty acids decreases fluidity