Why do we age? What appears to initiate the aging process and do we have any cellular mechanisms that control or facilitate this process?

Why do we age? What appears to initiate the aging process and do we have any cellular mechanisms that control or facilitate this process? This is the prompt i chose for my research paper and i just wanted to add that there needs to be some pictures involved that have to do with the paragraphs like charts and statistics. a bibliography and in text citations for the scholarly sources are also mandatory for this research essay.