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.
When you work and pay Social Security taxes, you earn credits toward Social Security benefits. To qualify for Medicare at age 65, you need 40 credits or 10 years of work. You may qualify for Medicare through your own earnings history, your current spouse, former spouse or deceased spouse.