Question

nine months after conception, a baby named tracy is born. the periods of tracys prenatal development from first to last were:
zygote, embryo, and fetus.
embryo, zygote, and fetus.
zygote, fetus, and embryo.
fetus, embryo, and zygote.

Explanation:

Prenatal development begins with the zygote (fertilized egg), then develops into an embryo (weeks 3 - 8), and finally becomes a fetus (from week 9 until birth).

Answer:

zygote, embryo, and fetus.