What explains why aging occurs?

• A. Physical decline
• B. Theories of aging
• C. Altruistic suicide
• D. Research thanatologists

Answer: (B)

The main concept being tested is that aging is explained by theories of aging. These theories provide scientific explanations for why aging happens, offering mechanisms like genetic programming, accumulated cellular damage, and metabolic byproducts that drive the gradual decline in function over time. They give a framework for understanding patterns across individuals and species, not just describing what aging looks like. Observing physical decline describes the outcomes of aging, but it doesn’t explain the underlying processes. Altruistic suicide and the field of thanatology relate to other topics—one is a social concept, the other studies death and dying—so they don’t address why aging occurs.