This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
A shift to the right in the biological activity dose- response curve for a hormone with no accompanying change in the maximal response indicates: 
Select and explain. 
A. Decreased responsiveness and decreased sensitivity, B. Increased responsiveness, C. Decreased sensitivity, D. Increased sensitivity and decreased responsiveness
C: Decreased sensitivity
Answer: C: Decreased sensitivity 
Explanation: Ans. C. Decreased sensitivityRight or left shifts in dose-response curves indicate changes in sensitivity. Changes in maximal biological response indicate changes in responsiveness. Because there is no change in maximal response, the correct answer must relate to a change in sensitivity only. A right shift indicates decreased sensitivity.