2: Theories of Aging Last updated Save as PDF Page ID 84769 Lumen Learning Lumen Learning 2.1: Theories of Aging 2.2: Theory 1- Aging by Program 2.3: Theory 2- Gene Theory 2.4: Theory 3- Autoimmune Theory 2.5: Theory 4- Wear-and-Tear Theory 2.6: Theory 5- Rate of Living Theory 2.7: Theory 6- Free Radical Theory 2.8: Theory 7- Cross-linkage Theory