This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
Which of the following moves rapidly across the membrane? 
Select and explain. 
A. CO2, B. Water, C. Glucose, D. Urea
A: CO2
Answer: A: CO2 
Explanation: Hydrophobic molecules move rapidly across the membrane