Questions: The usual site of implantation of the blastocyst is the uterine tube

The answer is the first one: uterus.

Explanation for each option:

• Uterus: This is the correct answer. The usual site of implantation for a blastocyst is the endometrial lining of the uterus. This is where the embryo can properly implant and develop during pregnancy.

• Vagina: This is incorrect. The vagina is part of the female reproductive tract, but it is not the site of implantation. It serves as the passageway for menstrual flow, intercourse, and childbirth.

• Ovary: This is incorrect. The ovaries are responsible for producing eggs (ova) and hormones, but they are not the site of implantation. An ectopic pregnancy can occur if implantation happens here, which is a medical emergency.

• Uterine tube: This is incorrect. Also known as the fallopian tube, it is where fertilization typically occurs, but it is not the usual site of implantation. An ectopic pregnancy can occur if implantation happens in the uterine tube, which is also a medical emergency.

In summary, the usual site of implantation of the blastocyst is the uterus.