Final answer:
A zygote undergoes several cell divisions to become a morula and then a blastocyst, which implants in the uterine wall becoming an embryo. The correct order of prenatal development is zygote, embryo, and then fetus. Thus, during development, the zygote becomes an embryo.d) embryo.
Step-by-step explanation:
During the course of prenatal development, a zygote is the initial single-cell structure formed when a sperm and an egg merge at conception. As the zygote travels toward the uterus, it undergoes several cell divisions, ultimately forming a multi-cell structure known as a morula, which further develops into a blastocyst. This blastocyst then implants in the uterine wall and at this point is referred to as an embryo. The correct order of prenatal development is zygote, embryo, then fetus. During development, the zygote becomes a(n) embryo.
The placenta plays a critical role in the developing fetus's life, providing nourishment and oxygen via the umbilical cord. The germinal stage includes the early cell divisions and stages of the zygote, morula, and blastocyst, leading up to when the blastocyst becomes an embryo upon implantation in the uterus. The embryonic stage then starts and continues until the eighth week, followed by the fetal stage from the ninth week until birth.