Correct Answer: B

Rationale: The correct answer is B: By altering immune development. The maternal microbiome plays a crucial role in shaping the fetal immune system during pregnancy. Microbes in the mother's body can influence the development of the fetus's immune system through various mechanisms, such as immune cells crossing the placenta. This interaction helps the fetus develop tolerance to maternal antigens. Choice A (By increasing fetal weight) is incorrect because the maternal microbiome's influence is not primarily related to weight gain. Choice C (By reducing placental oxygen levels) is incorrect as it does not directly relate to the immune system development. Choice D (By enhancing amniotic fluid) is incorrect as the main influence is on the immune system rather than amniotic fluid enhancement.

Correct Answer: C

Rationale: The correct answer is C: Truncus arteriosus. In this congenital heart defect, a single large blood vessel arises from the heart instead of the normal two separate vessels (aorta and pulmonary artery). This results in mixing of oxygenated and deoxygenated blood, leading to severe cyanosis and inadequate oxygen supply to the body. This condition is incompatible with life, causing immediate death after birth. A: Pulmonary stenosis and B: Aortic coarctation are also congenital heart defects but do not typically result in immediate death after birth. Pulmonary stenosis obstructs blood flow to the lungs, while aortic coarctation causes narrowing of the aorta. D: Ductus arteriosus is a normal fetal blood vessel that connects the pulmonary artery and the aorta but usually closes shortly after birth. Failure of closure can lead to health issues, but it is not typically a cause of immediate death after birth.

Correct Answer: D

Rationale: The correct answer is D because skin-to-skin contact after birth offers multiple benefits. Firstly, it helps stabilize the baby's temperature by utilizing the parent's body heat. Secondly, it promotes bonding between the parent and baby through physical closeness and touch. Finally, it can regulate the baby's heartbeat by providing a calming and reassuring environment. Therefore, all of the above choices are correct in highlighting the significance of skin-to-skin contact after birth.

Correct Answer: A

Rationale: Rationale for choice A: Calcium channel antagonists are the treatment of choice for achalasia as they help relax the lower esophageal sphincter, improving swallowing. This is a non-invasive option that can provide symptom relief for many patients. Summary for other choices: B: Intrasphincter botulinum injection is a temporary solution and not considered the treatment of choice. C: Pneumatic dilation is another option for achalasia but is typically used if calcium channel antagonists are ineffective. D: Myotomy and partial fundoplication is a more invasive surgical option and usually considered if other treatments fail.

Correct Answer: B

Rationale: Congenital retraction of the prepuce, leading to permanent glans exposure, describes paraphimosis. This condition occurs when the foreskin is pulled back and cannot return to its normal position, causing pain and swelling. Phimosis (A) is the inability to retract the foreskin over the glans. Hypospadias (C) is a urethral opening on the underside of the penis. Hermaphroditism (D) is a rare condition of having both male and female reproductive organs. Paraphimosis (B) is the specific term for the given scenario.