The structure that will form the embryo is the inner cell mass. The inner cell mass is a group of cells located within the blastocyst, a hollow sphere of cells that forms early in embryonic development. The inner cell mass is situated on one side of the blastocyst and is exposed to the blastocoel, the fluid-filled cavity inside the blastocyst. The inner cell mass will give rise to the embryonic disc, which will eventually form the embryo itself, as well as the extraembryonic membranes that support the developing embryo. The cytotrophoblast and syncytiotrophoblast are both components of the trophoblast, an outer layer of cells that surrounds the inner cell mass and contributes to the formation of the placenta. The amniotic cavity is a fluid-filled space that forms within the embryonic disc, and will eventually give rise to the amniotic sac that surrounds and protects the developing embryo.
ANSWER: INNER CELL MASS