Why might certain young people be underweight?

Correct Answer: A

Rationale: Certain young people might be underweight because they are growing in height faster than they are gaining weight. During periods of rapid growth, the body's energy requirements are primarily directed towards height growth rather than weight gain, resulting in some individuals being underweight despite consuming sufficient calories. Choice B is incorrect because the question focuses on reasons related to growth rather than diet composition. Choice C is incorrect as it suggests overeating rather than the specific growth-related issue of height surpassing weight gain. Choice D is incorrect as it addresses nutritional variety rather than the growth dynamics affecting weight.

Correct Answer: D

Rationale: The correct answer is D because the urinary system eliminates some waste products of digestion. After digestion in the digestive system, nutrients are absorbed into the bloodstream, and waste products are transported to the kidneys via the urinary system to be excreted as urine. This process helps eliminate waste products generated during digestion, illustrating the coordination between the digestive and urinary systems. Choices A, B, and C are incorrect. Choice A is incorrect as the ureter is part of the urinary system, not controlled by the digestive system. Choice B is incorrect as the urinary system primarily removes metabolic waste, not toxins from digestion. Choice C is incorrect because the digestive system mainly aids in digestion and nutrient absorption, not hormone production affecting urination.

Correct Answer: B

Rationale: The adrenal gland is located superior to the kidney. Each kidney is surrounded by an adrenal gland, also known as the suprarenal gland, situated on top of the kidneys. The pituitary gland (A) is located in the brain, while the hypothalamus (C) is also in the brain, above the pituitary gland. The pancreas (D) is located in the abdomen, near the stomach and small intestine, not superior to the kidney.

Correct Answer: B

Rationale: The urethra belongs to both the urinary and reproductive systems. In the urinary system, it functions as a passage for urine from the bladder to exit the body. In the reproductive system, it serves as a conduit for the expulsion of semen during ejaculation. Choice A is incorrect because the urethra is not part of the endocrine system. Choice C is also incorrect because the urethra is not primarily associated with the endocrine system. Choice D is incorrect as the urethra is not part of the digestive or cardiovascular systems.

Correct Answer: D

Rationale: The correct answer is D, the radius. The axial skeleton comprises bones located along the central axis of the body. It includes the skull, ribs, breastbone (sternum), vertebrae, and sacrum. The radius, on the other hand, is a bone of the forearm, part of the appendicular skeleton. The appendicular skeleton consists of the bones of the limbs and their girdles, not the central axial bones.