Where does the blastocyst implant to become an embryo?
The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. The fertilized ovum divides to become a blastocyst, which implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth. Due to anatomical barriers such as the pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. Even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).
In what lining does the blastocyst implant, in order to become an embryo?
endometrium
Uterus
"In vitro" fertilization (IVF) is an alternative to traditional "in vivo" fertilization for fertilizing an egg with sperm and implanting that embryo into a female’s womb. For many years the embryo was inserted into the uterus two to three days after fertilization. However at this stage of development it is very difficult to predict which embryos will develop best, and several embryos were typically implanted. Several implanted embryos increased the likelihood of a developing fetus but also led to the development of multiple fetuses. This was a major problem and drawback for using embryos in IVF.
In what organ does the blastocyst implant, in order to become an embryo?
uterus
Blastocyst
The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. The fertilized ovum divides to become a blastocyst, which implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth. Due to anatomical barriers such as the pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. Even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).
Where does the blastocyst implant when it's an ectopic pregnancy?
fallopian tube
Uterus
Uterus
https://en.wikipedia.org/wiki/Uterus
Blastocyst
https://en.wikipedia.org/wiki/Blastocyst
About seven days after fertilization,[1] the blastocyst undergoes implantation, embedding into the endometrium of the uterine wall.
Blastocyst
 Most ectopic pregnancies (90%) occur in the fallopian tube, which are known as tubal pregnancies,[2] but implantation can also occur on the cervix, ovaries, cesarean scar, or within the abdomen
Ectopic pregnancy
Implantation in the uterine wall allows for the next step in embryogenesis, 
Blastocyst
About seven days after fertilization, the blastocyst undergoes implantation, embedding into the endometrium of the uterine wall. Implantation in the uterine wall allows for the next step in embryogenesis. An ectopic pregnancy is a complication of pregnancy in which the blastocyst implants outside the uterus.  Most ectopic pregnancies occur in the fallopian tube, which are known as tubal pregnancies. However, an ectopic pregnancy can also occur with implantation of the blastocyst on the cervix, ovaries, cesarean scar or within the abdomen. 