Answer:
Day 1: The blastocyst begins to hatch out of its shell.
Day 2: The blastocyst continues to hatch out of its shell and begins to attach itself to the uterus.
Day 3: The blastocyst attaches deeper into the uterine lining, beginning implantation
Explanation:
Stage. Days (approx) Events.
4. 5 - 6. attaching blastocyst
5. 7 - 12 (week 2) implantation.
6. 13 - 15. extraembryonic mesoderm, primitive streak, gastrulation
7. 15 - 17 (week 3) gastrulation, notochordal
