Correct Answer: D

Rationale: Newborns have a higher percentage of body water compared to adults due to their higher body fluid content. Factors such as the higher ratio of body surface area to body volume and lower body fat content contribute to this. This is why a newborn would have the greatest percentage of body water. Choices A, B, and C are incorrect because obesity and gender do not determine the percentage of body water in individuals. Therefore, the correct answer is a newborn.

Correct Answer: C

Rationale: The correct answer is C: Protein in the blood plasma. Plasma proteins, especially albumin, create oncotic pressure, which is the main force responsible for holding water within the blood capillaries. Capillary blood pressure (Choice A) is involved in pushing blood through the capillaries, while sodium and chloride in the blood plasma (Choices B and D) are electrolytes and do not play a significant role in the water-holding force within capillaries.

Correct Answer: D

Rationale: The correct answer is D. Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity. Choice A is incorrect because glucose does not form electrolytes when added to water. Choice B is incorrect as it states that electrolytes dissociate but do not form ions, which is inaccurate as electrolytes do form ions in water solutions. Choice C is also incorrect as it states that electrolytes form ions but may not necessarily dissociate, which goes against the definition of electrolytes that must dissociate into ions for conductivity. Therefore, choice D is the most accurate as it correctly describes that electrolytes dissociate in water solutions and form ions, highlighting the essential characteristics of electrolytes.

Correct Answer: C

Rationale: The correct answer is C: increased aldosterone secretion. Aldosterone, a hormone produced by the adrenal glands, increases sodium reabsorption in the kidneys, leading to retention of sodium and water in the interstitial fluid. Increased aldosterone secretion enhances the reabsorption of sodium, thereby increasing its retention. Choice A is incorrect because decreased aldosterone secretion would lead to less sodium reabsorption and increased excretion. Choice B is incorrect because increased ADH secretion primarily affects water reabsorption rather than sodium. Choice D is incorrect because decreased ADH secretion would lead to increased water excretion but not necessarily affect sodium retention.

Correct Answer: D

Rationale: A low pH indicates acidosis (normal pH is 7.35 to 7.45). The PaCO2 is also low, which causes alkalosis. The bicarbonate is low, which causes acidosis. The pH bicarbonate more closely corresponds with a decrease in pH, making the metabolic component the primary problem. Therefore, the correct interpretation of the arterial blood gas results is metabolic acidosis with a compensatory respiratory alkalosis. Choices A, B, and C are incorrect because they do not accurately reflect the primary acid-base disturbance and the compensatory response seen in the given results.