Correct Answer: A

Rationale: The correct answer is A: Placenta. The placenta is a temporary organ that connects a mammalian mother to its foetus. It plays a crucial role in facilitating the exchange of nutrients, oxygen, and waste between the mother and the developing baby. Choice B, Chorion, is incorrect as it is a part of the fetal membrane but not the organ that connects the mother to the fetus. Choice C, Endometrium, is incorrect as it is the lining of the uterus where implantation occurs but is not the organ responsible for connecting the mother to the fetus. Choice D, None of the above, is incorrect as the placenta specifically fits the description provided in the question.

Correct Answer: A

Rationale: During the menstrual cycle, luteinizing hormone maintains the corpus luteum. The correct answer is A. Luteinizing hormone stimulates the corpus luteum to produce progesterone. Choice B, Follicle-stimulating hormone, is involved in stimulating the growth of follicles in the ovaries. Choice C, Progesterone, is produced by the corpus luteum and plays a role in preparing the endometrium for implantation. Choice D, Relaxin, is involved in processes such as softening the cervix and ligaments during pregnancy, but it is not responsible for maintaining the corpus luteum.

Correct Answer: B

Rationale: The correct answer is B: Squamous epithelium. The vagina is lined with non-keratinized stratified squamous epithelium. This type of epithelium provides protection against abrasion and pathogens. Choice A, Ciliated epithelium, is incorrect as ciliated epithelium is found in areas like the fallopian tubes to help move the egg towards the uterus. Choice C, Columnar epithelium, is incorrect as columnar epithelium is typically found in areas like the intestines. Choice D, Transitional epithelium, is incorrect as this type of epithelium is found in areas like the urinary bladder.

Correct Answer: B

Rationale: In incomplete abortions, the products of conception are retained. In a complete abortion, all the products of conception are expelled from the uterus. Threatened abortion refers to a situation where there is vaginal bleeding but the cervix remains closed, and it does not necessarily involve retention of products of conception. Mixed abortion is not a recognized medical term related to retained products of conception.

Correct Answer: B

Rationale: The correct answer is B: Rectum. The rectum is located posterior to the vagina in the pelvic cavity. The Pouch of Douglas (choice A) is a peritoneal pouch located between the rectum and the uterus. The perineal body (choice C) is a fibrous structure located between the vagina and the anus. Structures of the vulva (choice D) are external genital structures surrounding the vaginal opening, not posterior to the vagina.