A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke.
If you were born in 1929 or later, you need to work at least 10 years to become eligible for Social Security. The SSA determines eligibility with a system of credits. Basically, you earn up to four credits for every year worked, and you need a total of 40 credits to qualify for Social Security.
For Social Security retirement benefits, you must be between the ages of 62 and 70 to start collecting benefits. To check on your eligibility, see Nolo's article Checking you Social Security Earnings and Benefits or call the Social Security Administration at 800-772-1213. The Social Security Administration used to consider 65 to be full retirement age for the retirement benefit.