Each of us began our journey of life as a single-cell zygote—
the product of the fusion of the genetic material from our father’s sperm cell and our mother’s ovum.
This activity tells the story of the first step in the journey of life—the phases of development between conception and birth.
During the first 2 weeks—the germinal phase of prenatal development—the single cell becomes a mass of cells,
doubling again and again as it moves down the fallopian tube before implanting in the wall of the mother’s uterus.
During weeks 3 through 8—the embryonic phase—the mass of cells begins to draw nutrients from the mother’s blood,
and each organ system begins to form.