What organ connects the embryo to the uterine wall and provides nutrients?

The placenta is the organ that forms during pregnancy to connect the developing embryo to the uterine wall. Its primary function is to facilitate the transfer of nutrients, gases, and waste products between the mother and the embryo. The placenta serves as an interface, allowing essential substances such as oxygen and glucose to pass from the mother's bloodstream to the embryo while removing carbon dioxide and waste materials from the embryo back to the mother's circulation for disposal.

In addition to nutrient exchange, the placenta also plays a critical role in hormone production, supporting the pregnancy, and providing a barrier to certain pathogens. This multifunctionality makes the placenta essential for the health and development of the embryo throughout gestation.

While the amniotic sac serves a protective role by containing the amniotic fluid that cushions the embryo, and the blastocyst is an early stage of embryo development that eventually implants into the uterine wall, neither of these structures is responsible for the direct transfer of nutrients. The fetus is the developing organism itself after the embryonic stage and does not participate in connecting to the uterine tissue or nutrient transfer. Therefore, the placenta is uniquely positioned as the organ that fulfills these vital functions.