Correct Answer: A

Rationale: African-Americans have a higher risk of developing hypertension compared to other ethnic groups. They tend to develop high blood pressure at younger ages and are more sensitive to salt, which increases their risk of hypertension. Additionally, studies have shown that African-Americans may respond differently to hypertensive drugs. Therefore, the 45-year-old African-American attorney is at the greatest risk for developing hypertension. The other choices do not specify factors that put them at a higher risk for hypertension compared to African-Americans.

Correct Answer: D

Rationale: Hirschsprung's disease, also known as congenital aganglionosis or aganglionic megacolon, is a congenital anomaly characterized by an absence of ganglion cells in the rectum and other areas of the affected intestine. A key clinical manifestation of Hirschsprung's disease is chronic constipation that starts in the first month of life, leading to pellet-like or ribbon-like stools that have a foul smell. Another sign is the delayed passage or absence of meconium stool in the neonatal period. In addition to foul-smelling, ribbon-like stools, bowel obstruction (especially in the neonatal period), abdominal pain and distention, and failure to thrive are also common clinical manifestations of this disorder. Options A, B, and C are not typically associated with Hirschsprung's disease, making them incorrect choices in this scenario.

Correct Answer: A

Rationale: Hirschsprung's disease, also known as congenital aganglionosis or megacolon, is characterized by the absence of ganglion cells in the rectum and, sometimes, extending into the colon. Choice A correctly explains the cause of Hirschsprung's disease. Choice B is incorrect as it describes celiac disease, which is related to gluten intolerance. Choice C is inaccurate as it describes symptoms of irritable bowel syndrome, not the cause of Hirschsprung's disease. Choice D is wrong as it pertains to lactose intolerance, not Hirschsprung's disease.

Correct Answer: A

Rationale: The major difference between a grand mal and petit mal seizure is the presence or absence of convulsive movements. Grand mal seizures are characterized by convulsive movements, including jerking of limbs and loss of consciousness. In contrast, petit mal seizures, also known as absence seizures, typically involve brief episodes of staring or eye blinking without convulsive movements. Therefore, choice A, 'convulsive movements,' is the correct answer. Choices B, 'sleep apnea,' and D, 'flaccidity,' are incorrect as they are not associated with the characteristics of grand mal or petit mal seizures. Choice C, 'atonic movements,' is also incorrect as petit mal seizures do not involve atonic movements, but rather absence behaviors such as staring spells.

Correct Answer: A

Rationale: African-Americans have a higher risk of developing hypertension compared to other ethnic groups. They tend to develop high blood pressure at younger ages and are more sensitive to salt, which increases their risk of hypertension. Additionally, studies have shown that African-Americans may respond differently to hypertensive drugs. Therefore, the 45-year-old African-American attorney is at the greatest risk for developing hypertension. The other choices do not specify factors that put them at a higher risk for hypertension compared to African-Americans.