Correct Answer: C

Rationale: The correct answer is C: 'adjust fluid output so it equals fluid input.' Maintaining fluid balance involves ensuring that the amount of fluid lost through processes like urination, sweating, and respiration equals the amount of fluid taken in. This ensures that the body stays properly hydrated. Choices A, B, and D are incorrect because they do not focus on the balance between fluid input and output, which is crucial for maintaining proper fluid balance. By adjusting fluid output to equal fluid input, the body can regulate hydration levels effectively, preventing dehydration or overhydration.

Correct Answer: B

Rationale: The correct answer is 'Intracellular fluid.' Intracellular fluid refers to the fluid contained within the cells, constituting a significant portion of the body's total water content. Choices A, C, and D are incorrect. Plasma is the liquid component of blood outside the cells, interstitial fluid is the fluid surrounding cells in tissues, and the combination of plasma and intracellular fluid is not the specific term for the fluid inside the cell.

Correct Answer: C

Rationale: Dehydration leads to a decrease in the body's fluid levels, causing the salivary glands to produce less saliva, resulting in a dry mouth. Therefore, when dehydration begins to occur, salivary secretions decrease. Choice A is incorrect because the body does not reduce fluid output to zero during dehydration; it tries to conserve fluids. Choice B is incorrect as dehydration does not directly increase the release of ANH (Atrial Natriuretic Hormone). Choice D is incorrect because salivary secretions do not increase but decrease during dehydration.

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: B

Rationale: The correct answer is B: Osmosis and osmolality. Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. In this case, the hypertonic solution increases the number of dissolved particles in the blood, causing fluids to shift into the capillaries due to the osmotic pressure gradient. Osmolality refers to the concentration of solutes in a solution. Hydrostatic pressure refers to changes in water or volume related to water pressure, not the movement of fluids due to solute concentration differences. Diffusion is the movement of solutes from an area of greater concentration to lesser concentration; in an intact vascular system, solutes are unable to move freely, so diffusion does not play a significant role in this scenario. Active transport involves the movement of molecules against the concentration gradient with the use of energy, typically at the cellular level, and is not related to the vascular volume changes described in the question.