After 12-14 days, the egg enters the uterus. By this time, the mucous membrane of the uterus becomes loose. If the egg is fertilized, the resulting multicellular embryo attaches to the uterine wall. An unfertilized egg cannot be fixed and goes out together with a loose layer that has separated from the inner surface of the uterine wall. Bleeding begins – menstruation.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.