Implantation begins about 6–7 days after ovulation; in this process, the cells of the trophoblast which are closest to the inner cell mass _____. This process continues until the blastocyst is _____, and takes several days.

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.