The provides oxygen and nutrients to the growing fetus and removes waste products from its blood. it attaches to the wall of the uterus and the umbilical cord arises from it.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.