What occurs during germinal period and when does the

5. What occurs during germinal period and when does the period begin and end (p.
58-59)? What is the organism called during this period? (zygote)
6. When does implantation typically occur?
7. When is & what occurs during the embryo/embryonic period (p. 59)?
8. What are the three cell layers the embryo has at this time?
9. When is and what occurs during the fetus/fetal period (p. 59)?

10. How do these three periods compare to trimesters (p. 60)?
11. Define placenta (p. 59), umbilical cord, HCG, organogenesis (p.59), amnion (p.
59) ectoderm, mesoderm, endoderm. According to your text, how far along in gestation is
the age of viability (p. 60)? What is a critical period (lecture)?