This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lipids, Subject name: Biochemistry
Lipid peroxidation as a part of ageing and injury of cells is: 
Select and explain. 
A. Free radical theory, B. Apoptosis theory, C. Enzyme cascade theory, D. Cell destruction theory
A: Free radical theory
Answer: A: Free radical theory 
Explanation: A