Final answer:
The placenta is the organ that connects the developing fetus to the uterine wall for nutrient uptake, waste elimination, and gas exchange via the mother's blood supply.
Step-by-step explanation:
The organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply is the placenta.
In mammals, the placenta is a temporary organ that forms during pregnancy. It acts as a conduit between the mother and fetus, allowing the transfer of nutrients, oxygen, antibodies, and other substances while removing waste products. The placenta develops from the chorion and functions as a circulatory organ.
The placenta is essential for the development and survival of the fetus, ensuring its nourishment and gas exchange with the mother's blood supply.