Question

the cluster of cells that develops by the end of the first 2 weeks of pregnancy is called the:
× zygote.
placenta.
embryo.
fetus.

Explanation:

In prenatal development, the zygote is the initial stage after fertilization. By the end of the first 2 weeks of pregnancy, the developing structure is called the embryo. The placenta is an organ that forms later to provide nutrients and oxygen to the fetus. The fetus is the stage of development from about 8 - 9 weeks of pregnancy onwards.

Answer:

embryo.