In what order does prenatal development occur?

Prenatal development follows a specific sequence that is crucial for the formation of a healthy human being. The correct order begins with the zygote, which is the fertilized egg formed when a sperm cell successfully merges with an ovum. This stage lasts for about the first week after conception.

Following the zygotic stage, the zygote undergoes multiple cell divisions and becomes a blastocyst. This early developmental stage attaches itself to the uterine wall and transitions into the embryonic stage, known as the embryo. This stage lasts until about the end of the eighth week of gestation, during which the foundations for all major organ systems are established.

Finally, after the embryonic stage, the developing human is referred to as a fetus. This period starts from the ninth week of gestation and continues until birth, characterized by significant growth and maturation of the organs and bodily systems formed in the earlier stages.

The correct sequence—zygote, embryo, and then fetus—accurately reflects the developmental milestones that occur during pregnancy and demonstrates the structured nature of human development prior to birth.