This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Not a stimulus for pulmonary vasoconstriction: 
Select and explain. 
A. Hypoxemia, B. Hypercapnia, C. PGI2, D. Thromboxane
C: PGI2
Answer: C: PGI2 
Explanation: C i.e. PGI2The unique feature of pulmonary vasculature is that the hypoxia tends to produce Vasconstriction (where as in other system it produces Vasodilation)