What term describes each individual cell within the blastocyst?

The term that describes each individual cell within the blastocyst is "blastomere." During the early stages of embryonic development, after fertilization, the initial zygote undergoes a series of mitotic divisions, resulting in smaller cells known as blastomeres. These blastomeres continue to divide as they form the blastocyst, which is a hollow sphere made up of an inner cell mass and an outer layer of cells.

In this context, the inner cell mass eventually develops into the embryo, whereas the outer layer of cells, which is not referred to as blastomeres, becomes the trophoblast that contributes to the placenta. The term "embryoblast" specifically refers to the inner cell mass of the blastocyst that will develop into the actual embryo. "Neoplasm," on the other hand, typically refers to an abnormal growth of tissue or tumor, which does not apply to the normal structures in the blastocyst development. Thus, "blastomere" is the most accurate term to describe the individual cells formed during the early cleavage stages leading up to the formation of the blastocyst.