Name the three stages of pregnancy and the major anatomical structures involved in each stage.

• A. Germinal stage (zygote, morula, blastocyst in fallopian tube); Embryonic stage (organogenesis with placenta and amniotic sac; weeks 3-8); Fetal stage (growth and maturation of organs; weeks 9 to birth).
• B. Germinal stage (zygote in uterus); Embryonic stage (bone development); Fetal stage (postnatal life).
• C. Embryonic stage (organogenesis with placenta and amniotic sac); Germinal stage (zygote, morula, blastocyst in fallopian tube); Fetal stage (growth and maturation of organs).
• D. Fetal stage (growth and maturation); Germinal stage; Embryonic stage.

Answer: (A)

The stages of pregnancy are defined by key developmental milestones and the structures that support the growing conceptus. In the germinal stage, fertilization begins the process, and the zygote progresses to morula and then blastocyst while moving toward the uterus; this stage occurs in the fallopian tube and ends with implantation into the uterine lining. Moving into the embryonic stage, which spans roughly weeks 3–8, organogenesis takes place and the major supporting structures become established—the placenta begins to form and the amniotic sac surrounds the developing embryo, creating a protective environment and a site for nutrient/gas exchange. Finally, the fetal stage runs from week 9 to birth, characterized by growth and maturation of already-formed organs, with the placenta continuing to provide nourishment and waste removal as the fetus grows. This ordering and these structures fit the described stages precisely.