question: What cycle occurs in women of reproductive age, as a long as a sperm does not enter an egg?
distractor3: menopausal cycle
distractor1: extraction cycle
distractor2: tissue cycle
correct_answer: menstrual cycle
support: If a sperm does not enter an egg, the lining of the uterus breaks down. Blood and other tissues from the lining break off from the uterus. They pass through the vagina and out of the body. This is called menstruation . Menstruation is also called a menstrual period. It lasts about 4 days, on average. When the menstrual period ends, the cycle repeats. Some women feel discomfort during this process.