Final answer:
The decidua basalis and the chorionic villi grow together to form the placenta, which is the location of nutrient and waste exchange between the mother and fetus. option d is correct.
Step-by-step explanation:
The decidua basalis of the endometrium and the chorionic villi of the fetus grow together to form the placenta. The decidua basalis is the maternal portion that develops from the deepest layer of the endometrium, while the chorionic villi make up the fetal portion of the placenta.
These villi, which are finger-like projections from the chorion, penetrate the endometrium and establish the site of nutrient and waste exchange between the mother and the fetus. Throughout development, the cytotrophoblast cells and the extraembryonic mesoderm contribute to the formation of the chorionic membrane that encloses the entire conceptus and forms the chorionic villi, facilitating the development of the placenta.
The decidua basalis, which is part of the endometrium, and the chorionic villi of the fetus come together to form the placenta. The placenta is a vital organ during pregnancy that facilitates the exchange of nutrients, oxygen, and waste products between the mother and the developing fetus. The amnion, ectoderm, blastocyst, and morula are distinct structures in embryonic development, and they do not directly contribute to the formation of the placenta in the same way as the decidua basalis and chorionic villi.