The placenta that is attached to the babys belly button. That's how the baby gets most of it's nourishment. Also the amniotic fluid plays a role in it as well.
Placenta
placenta
The uterus is the hollow muscular organ that protects and nourishes a developing fetus during pregnancy. It is located in the pelvis and has a lining that thickens each month to prepare for a possible pregnancy.
A flattened circular organ in the uterus of pregnant eutherian mammals, nourishing and maintaining the fetus through the umbilical cord. its from google
The placenta is the organ that nourishes the embryo during pregnancy. It is formed from the tissues of both the mother and the developing fetus and allows for the exchange of nutrients and waste products between the mother and the baby.
The structure that connects an embryo with the organ that nourishes it is called the umbilical cord. The umbilical cord attaches the developing fetus to the placenta, which is the organ responsible for providing nutrients and oxygen to the embryo or fetus while removing waste products. The umbilical cord contains blood vessels (two arteries and one vein) that carry deoxygenated blood and waste products away from the fetus and deliver oxygen and nutrients to the fetus from the placenta.
Eutherians are referred to as placental mammals because they have a placenta, which is an organ that nourishes the developing fetus during pregnancy.
The uterus nourishes the fertilized ovum.
Nutrients and other needed materials diffuse from the mother's blood through the placenta which connects the fetus the the uterus lining.
The umbilical cord supplies the fetus' oxygen.
uterus
The organ where the developing fetus resides is called the uterus. This is where the fetus grows and matures inside the female.