This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
[{'content': 'In a measurement of cardiac output using the Fick principle, the O concentrations of mixed venous and arterial blood are 16 and 20 ml-100 ml-1, respectively, and the O consumption is 300 ml-min-1. The cardiac output in liters-min-1 is: \nSelect and explain. \nA. 5, B. 8, C. 9, D. 7.5', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans: (d) 7.5Ref: Ganong, 25th edition, Page 543The Fick principle states that the cardiac output is equal to the oxygen consumption divided by the arterial- venous oxygen concentration difference.Here, its (20 -16) ml-100 ml-1 or (200 - 160) ml liter-1.Therefore, the cardiac output is equal to 300/(200 - 160) or 7.5 liters-min-1', 'role': 'assistant'}]