The _________ is a temporary organ that connects a mammalian mother to its foetus.

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: C

Rationale: Oligomenorrhea is defined as a menstrual cycle longer than 35 days. A cycle of 28 days (Choice A) is within the normal range, and not considered oligomenorrhea. Similarly, 30 days (Choice B) and 40 days (Choice D) are also within the normal range. The correct definition of oligomenorrhea specifically refers to cycles longer than 35 days, making Choice C the correct answer.

Correct Answer: B

Rationale: The correct answer is B: The corpus luteum produces progesterone to maintain the endometrium during the menstrual cycle. This hormone helps prepare the uterine lining for implantation in case fertilization occurs. Choice A is incorrect because estrogen is mainly produced by the developing follicles in the ovaries. Choice C is incorrect as testosterone is produced in smaller amounts by the ovaries and adrenal glands but does not play a significant role in maintaining the endometrium. Choice D is incorrect as the corpus luteum plays a crucial role in producing progesterone to support the endometrium.

Correct Answer: D

Rationale: The secretory phase is not considered a distinct phase of the menstrual cycle; it is actually part of the luteal phase. During the luteal phase, the endometrium thickens due to progesterone secretion, preparing for implantation. The follicular phase is characterized by follicle development, leading to ovulation. The ovulatory phase is when the mature egg is released from the ovary. Therefore, the secretory phase is the correct answer as it is not a standalone phase but a part of the luteal phase.

Correct Answer: D

Rationale: At 8-12 weeks of pregnancy, the breast changes typically include the onset of colostrum production, not just tenderness. Colostrum is the first milk produced by the mammary glands during pregnancy. While some women may experience prickling or tingling sensations, prominent and mobile nipples, and darkening of the nipple, the key change during this time period is the production of colostrum. This substance is rich in antibodies and important for the newborn's initial nutrition. Therefore, the correct answer is not listed among the choices provided.