If someone has endometriosis, what must be true?

Endometriosis occurs when tissue similar to the lining of the uterus grows outside the uterus, such as on nearby pelvic organs. It is not necessarily caused by an STI, and it does not mean the tissue has become tumors or has simply been shed from the body. Therefore, the correct choice is “Tissue from the uterus has moved out of the uterus.”

AI-written and checked against the verified answer.