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.
As you work and pay Social Security taxes, you earn credits toward your Social Security benefits. The number of years you need to work for your family to be eligible for Social Security survivors benefits depends on your age when you die. The younger you are, the fewer years you need to work. But no one needs more than 10 years of work to be eligible for any Social Security benefit. Under a special rule, if you have worked for only one and one-half years in the three years just before your death, benefits can be paid to your children and your spouse who is caring for the children.