This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy Pa 2, Subject name: Radiology
The most radiosensitive phase of cell cycle is: 
Select and explain. 
A. G2M interface, B. G2, C. S, D. M
A: G2M interface
Answer: A: G2M interface 
Explanation: Radiosensitivity of the cell cycle pahses : G2M > M > G2> G1> S. G2M is most Radiosensitive phase and S phase is most radioresistant phase