Question: Where does the blastocyst implant to become an embryo?
Answer: against the endometrium
Disambiguated annotations:
qaPairs: question: In what lining does the blastocyst implant, in order to become an embryo?
answer: endometrium
question: In what organ does the blastocyst implant, in order to become an embryo?
answer: uterus
question: Where does the blastocyst implant when it's an ectopic pregnancy?
answer: fallopian tube