The theory, methods, and practice of testing a hypothesis by comparing it with the null hypothesis. The null hypothesis is only rejected if its probability falls below a predetermined significance level, in which case the hypothesis being tested is said to have that level of significance.
I think the answer you are looking for is tobacco
Upper extremities is radius and ulna it's your hand bone.
This may be a sebaceous cyst. This type of bump develops when sebaceous glands are blocked. Sebum builds up and a bump develops. This bump can feel hard to touch. Sebum is naturally produced, so there usually is not inflammation.