Final answer:
The inner cell layer of a trophoblast is referred to as the embryoblast or inner cell mass, which will develop into the embryo, while the trophoblast contributes to the placenta.
Step-by-step explanation:
The inner cell layer of a trophoblast is called the embryoblast, which is also known as the inner cell mass. During mammalian development, after the blastula stage, the structure known as a blastocyst forms. The blastocyst consists of two distinct layers: the inner cell mass and the outer layer, the trophoblast. The inner cell mass or embryoblast will eventually develop into the embryo itself, whereas the cells of the outer layer, the trophoblast, will implant in the uterus and will contribute to the formation of the placenta and other structures necessary for supporting and nourishing the embryo. The cavity formed by the migration of embryoblast cells to one pole of the blastocyst and filled with fluid secreted by the trophoblast cells is known as the blastocoele.