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
Tachycardia is caused by hypoxia due to 
Select and explain. 
A. Reflexly through peripheral chemoreceptors, B. Diffuse vasodilation, C. Through central chemoreceptor, D. Secondarily after by hyperventilation
D: Secondarily after by hyperventilation
Answer: D: Secondarily after by hyperventilation 
Explanation: Tachycardia and vasodilation occur secondary to hyperventilation in cases of hypoxia. Central chemoreceptors do not have a role in hypoxia. Activation of peripheral chemoreceptors excites medullary vagal centre and causes Bradycardia.