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.
If you're still working, you can enroll in Medicare. You should file about three months before you turn 65, and if you have enough work credits under Social Security, apply for Medicare only. If you do not have enough work credits, you will need to file for Social Security and Medicare.