Give evidence in favour of mitochondrial theory of aging. What are its limitations? (UPSC 2014, 10 Marks, )

माइटोकॉन्ड्रियल सिद्धांत के पक्ष में साक्ष्य दें। इसकी सीमाएँ क्या हैं? (Give evidence in favour of mitochondrial theory of aging. What are its limitations?)