Of 2,872 persons who had received radiation treatment in childhood because of an enlarged thymus, cancer of the thyroid develope
d in 24 and a benign thyroid tumor developed in 52. A comparison group consisted of 5,055 children who had received no such treatment (brothers and sisters of the children who had received radiation treatment). During the follow-up period, none of the comparison group developed thyroid cancer, but benign thyroid tumors developed in six. Calculate the relative risk for benign thyroid tumors: _____
Parasitism is when one organism benefits and harms the organism it is living off of, while the organism it is living off of will only be harmed and does not benefit.