Answer the following question given this paragraph: The menstrual cycle is a series of changes in the reproductive system of mature females that repeats every month. While the egg and follicle are developing in the ovary, tissues are building up inside the uterus , the reproductive organ where the baby would develop. The uterus develops a thick lining covered in tiny blood vessels. This prepares the uterus to receive an egg that could develop into a child (a fertilized egg). The occurs during the first part of the cycle. Q: What is the series of changes in the reproductive system of a mature female that happens monthly? Choices: - urinary cycle - fetal cycle - pregnancy - menstrual cycle A:
A:
menstrual cycle