The Answer Is (a), (b), (c). I mean all of the above.
Answer:
6 days
Explanation:
once the embryo reaches the Blastocyst stage, approximately 5-6 days after fertilization, it hatches out of it's zona pellucida and begins the process of implantation in the uterus.
Yes it produces energy with cellular respiration. Which occurs in plants and animals etc.
