This question relates to Topic 8 (Part 3). a.Briefly explain the difference between ultimate and proximate theories of ageing. (2 marks) b.What is the difference between the mutation accumulation theory of ageing and the antagonistic pleiotropy theory? What evidence supports the latter, but not the former? (6 marks) c.List four potential molecular or cellular mechanisms that could contribute to cellular ageing, other than those that affect DNA in some respect. (2 marks)