Although transcellular fluids perform functional roles in the body, their collective volume forms a negligible fraction of total body water.

Correct Answer: A

Rationale: The correct answer is A because transcellular fluids, such as cerebrospinal fluid and synovial fluid, play essential functions in the body. However, their overall volume is relatively small compared to other body fluids like intracellular and extracellular fluids. Therefore, while transcellular fluids are important for specific functions, their total volume is indeed a negligible fraction of total body water. Choice B is incorrect because transcellular fluids do have functional roles, as mentioned earlier. Choices C and D are not applicable (NA) as they do not provide any relevant information to the question.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Sodium reabsorption in the kidneys is primarily regulated by the renin-angiotensin-aldosterone system and not the baroreceptor reflex. The baroreceptor reflex primarily regulates blood pressure through changes in heart rate and vascular tone. Therefore, choice B is correct. Choices A, C, and D are incorrect as they do not provide accurate explanations related to the regulation of sodium reabsorption in the kidneys.

Correct Answer: A

Rationale: The correct answer is A: TRUE. The extracellular fluid (ECF) volume and osmolarity are indeed primarily regulated by the kidneys. The kidneys control water and electrolyte balance in the body, adjusting urine concentration to maintain ECF volume and osmolarity within a narrow range. They regulate the reabsorption and excretion of water and electrolytes in response to hormonal signals and the body's needs. The other choices are incorrect as they do not provide any relevant information or explanation.

Correct Answer: A

Rationale: Step 1: Vasopressin is also known as antidiuretic hormone and helps regulate water balance by acting on the kidneys. Step 2: When the body detects a deficit of water, vasopressin is secreted to prevent water loss. Step 3: Therefore, the statement that vasopressin is normally secreted when a deficit of water develops in the body is true. Summary: Option A is correct because vasopressin is indeed secreted in response to water deficit. Options B, C, and D are incorrect as they do not provide the accurate explanation for the secretion of vasopressin in response to water deficit.

Correct Answer: B

Rationale: The correct answer is B: FALSE. The strength of an acid is determined by its tendency to donate protons, not by the speed of dissociation. HCl is a stronger acid than HCO3- because it completely dissociates into H+ and Cl- ions in water, while HCO3- only partially dissociates into H+ and HCO3- ions. Therefore, the statement that HCO3- is a weaker acid than HCl because it dissociates faster is incorrect. Choice A is incorrect because it does not consider the fundamental concept of acid strength. Choices C and D are not relevant to the question.