Deficiency or excess of water leads to which of the following changes?

• A. Increased bone density
• B. Improved acid-base balance
• C. Altered fluid and electrolyte balance
• D. No change in hydration status

Answer: (C)

Deficiency or excess of water disrupts how body fluids and electrolytes are distributed and concentrated. When water is deficient, plasma becomes more concentrated, increasing osmolality and shifting fluid from cells to the extracellular space; when water is excessive, plasma becomes diluted, reducing osmolality and diluting electrolytes like sodium. Either situation alters fluid and electrolyte balance, which is the direct and primary consequence of improper water balance. Increased bone density is not driven by hydration status, and while severe shifts can influence acid-base balance indirectly, the most consistent outcome described here is an altered fluid and electrolyte balance. No change in hydration status would be incorrect since hydration is inherently affected by water balance.