Correct Answer: A

Rationale: Limited access to contraceptives and family planning is indeed a major issue affecting adolescents in terms of sexual and reproductive health. This lack of access can lead to unintended pregnancies, sexually transmitted infections, and limited reproductive choices. Choice B, equal representation in decision-making, although important, is not directly related to sexual and reproductive health issues faced by adolescents. Choice C, decreased need for sexual education, is incorrect as proper sexual education is crucial in promoting healthy behaviors and preventing risks. Choice D, equal opportunities for career growth, is also unrelated to the specific issues surrounding sexual and reproductive health in adolescents.

Correct Answer: B

Rationale: Threatening abortion is characterized by a firm contracted uterus with an open os. This presentation indicates a risk of miscarriage. Choice A ('Os open') is not specific enough and does not fully describe the condition. Choices C ('Heavy bleeding') and D ('Severe cramping') can also be present in threatening abortion, but the primary characteristic is a firm contracted uterus with an open os.

Correct Answer: A

Rationale: Luteinizing hormone is responsible for maintaining the corpus luteum after ovulation. This is crucial for the production of progesterone, which helps prepare the endometrium for implantation and supports early pregnancy. Choices B, C, and D are incorrect: B is the function of follicle-stimulating hormone (FSH) which stimulates the growth of ovarian follicles, C is mainly regulated by prolactin, and D is primarily associated with estrogen and progesterone.

Correct Answer: C

Rationale: The correct answer is C: Pudendal arteries. The pudendal arteries are responsible for supplying blood to the external genitalia. These arteries specifically provide blood flow to the perineum, including the external genitalia. Choice A, Femoral arteries, are not primarily responsible for supplying blood to the external genitalia. Choice B, Inguinal arteries, do not supply blood directly to the external genitalia. Choice D, Internal iliac arteries, are not the main suppliers of blood to the external genitalia.

Correct Answer: B

Rationale: Bidder's canal is a part of the male reproductive system and receives sperm from the testes. The other choices are incorrect because Bidder's canal is not associated with receiving eggs, ammonia, or oxygenated blood.