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.
This is the reaction we hear most often when people find out that they've waited too long to file a Social Security Disability (SSD) claim. Many people don't know that you must have a certain number of work credits in order to file a SSD claim. The Social Security Administration determines the number of credits you have, which partially depends on how recently you've worked. These credits do expire, most within five years of when you stop working.