The correct option is Placenta.
Explanation
In placental mammals, the developing embryo requires a continuous supply of nutrients and oxygen, as well as a mechanism for waste removal. This is achieved through a specialized structural and functional unit formed between the developing embryo (fetus) and the maternal body.
Detailed Analysis:
- Placenta: After implantation, the chorionic villi from the embryo interdigitate with the uterine tissue to form the placenta. It acts as the physiological connection that facilitates the transport of oxygen and nutrients from the maternal blood to the embryo. Simultaneously, it allows for the removal of carbon dioxide and excretory waste materials produced by the embryo. It is connected to the embryo through the umbilical cord.
- Uterus: While the uterus (womb) is the organ where the fetus develops and is housed, the specific tissue responsible for the physiological exchange of materials is the placenta.
- Cervix: The cervix is the narrow canal connecting the uterus to the vagina. It functions as the birth canal during parturition but does not play a role in nutritional exchange.
- Oviduct (Fallopian Tube): This structure transports the ovum from the ovary and is the site of fertilization. It does not provide the physiological connection for nutrition during gestation.
Key Takeaway: The placenta is the essential interface for physiological exchange (nutrition, respiration, and excretion) between the maternal body and the fetus.