CBSE Class 10 Answered

Four phases of menstrual cycle: 1. Menstrual Phase: 1-5 days The lining of the wall of the uterus is shed off and it is discharged along with blood. 2. Follicular Phase: 5-12 days Graafian follicle into the ovary matures. The walls of the uterus start thickening. 3. Ovulatory Phase: 12th/13th/14th day Graafian follicle ruptures, and the mature ovum travels towards the uterus. 4. Luteal Phase: 15 – 28 days Uterus lining thickens further. If the fertilization takes place, the embryo gets implants into the walls of the uterus. If fertilization does not occur, then again the uterine walls is shed off and discharged and the cycle repeats.