The hormone(s) responsible for hymen. secondary sex characteristics in

Correct Answer: B

Rationale: The correct answer is B: estrogens. Estrogens are the primary hormones responsible for the development of secondary sex characteristics in females, including the formation of the hymen. Estrogens play a crucial role in regulating menstrual cycles, breast development, and overall reproductive health in females. Progesterone (choice D) is primarily involved in regulating the menstrual cycle and supporting pregnancy but is not directly responsible for hymen development. Choices A and C do not provide accurate or relevant information related to the development of secondary sex characteristics or the hymen.

Correct Answer: A

Rationale: The correct answer is A: just after fertilization. After fertilization, the secondary oocyte completes its second meiotic division, forming a mature ovum and a polar body. This process occurs to ensure the correct chromosome number in the resulting zygote. Choices B, C, and D are incorrect because the completion of the second meiotic division occurs specifically after fertilization, not before or just after ovulation or fertilization.

Correct Answer: D

Rationale: The correct answer is D: 23. Sperm cells are haploid, meaning they contain half the number of chromosomes as normal body cells. In humans, normal body cells have 46 chromosomes (23 pairs), while sperm cells have only 23 chromosomes. This is essential for maintaining the correct chromosome number after fertilization. A: 1 - Incorrect. Sperm cells cannot have only 1 chromosome as they need to contribute genetic material during fertilization. B: 2 - Incorrect. Having only 2 chromosomes would not provide sufficient genetic diversity for offspring. C: 12 - Incorrect. This number does not align with the haploid nature of sperm cells in humans with 23 chromosomes.

Correct Answer: B

Rationale: The correct answer is B: ovulation. Ovulation is the process where the ovarian follicle ruptures and releases an ovum. This occurs around the middle of the menstrual cycle. Menopause (A) is the cessation of menstrual periods, not the release of an ovum. Implantation (C) is the attachment of a fertilized egg to the uterine wall, not the release of an ovum. Breast (D) is not related to the process of ovulation.

Correct Answer: A

Rationale: The correct answer is A: dysmenorrhoea. Dysmenorrhoea specifically refers to abdominal pain caused by uterine cramps during menstruation. "Dys-" means difficult or painful, and "menorrhoea" refers to menstruation. Choice B, hypermenorrhoea, refers to abnormally heavy menstrual bleeding, not abdominal pain. Choice C, menometrorrhagia, refers to irregular and excessive uterine bleeding, not specifically related to abdominal pain. Choice D, polymenorrhoea, refers to frequent menstrual cycles, not abdominal pain. In summary, dysmenorrhoea is the correct answer because it accurately describes the abdominal pain associated with uterine cramps during menstruation, while the other choices pertain to different menstrual abnormalities.