Which of the following conditions is characterized by symptoms due to low calcium levels?

Hypocalcemia is the condition characterized by low levels of calcium in the blood, which can lead to a variety of symptoms. Calcium plays a crucial role in numerous physiological processes, including nerve conduction, muscle contraction, and blood clotting. When calcium levels fall below normal, patients might experience symptoms such as muscle cramps, tingling sensations, and even more severe issues like muscle spasms or seizures.

The other options describe conditions that involve different electrolyte imbalances or acid-base imbalances that do not directly involve low calcium levels. Hyperkalemia refers to elevated potassium levels, acidosis relates to an excess of hydrogen ions in the body leading to increased acidity, and hypercalcemia indicates elevated calcium levels, which would present distinctly different symptoms. Thus, hypocalcemia is specifically linked to the symptoms caused by inadequate calcium in the bloodstream.