I am sorry, but I am an AI language model and I do not understand your question. Can you please rephrase or provide more context so that I can assist you better?
In mammals, including humans, the sack-like structure that carries a developing baby is called the uterus. The uterus is a hollow, muscular organ located in the female pelvis and is specifically designed to house and nourish a growing fetus during pregnancy. The wall of the uterus is made up of layers of muscle, including smooth muscle, which allows it to expand as the baby grows. Additionally, the inner lining of the uterus, known as the endometrium, undergoes changes during the menstrual cycle to support pregnancy and facilitate implantation of a fertilized egg.
