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
Changes in biological activity occurring daily are
referred as  __________ rhythm: 
Select and explain. 
A. Circadian, B. Circa triginatan, C. Circa sestin, D. Circannual
A: Circadian
Answer: A: Circadian 
Explanation: None