Final answer:
Gestation refers to the period of development in the uterus from conception until birth, consisting of several stages including pre-embryonic, embryonic, and fetal.
Step-by-step explanation:
Gestation is the period of development in the uterus from conception to birth. This period includes several stages: the pre-embryonic stage, embryonic stage, and the fetal stage. The pre-embryonic stage encompasses the first two weeks of development post-fertilization, while the embryonic stage occurs during weeks 3-8, characterized by cell division, migration, and differentiation. The fetal stage begins from the ninth week and continues until childbirth, during which all of the organ systems mature. In humans, the gestation period lasts approximately 266 days.