Which of the following is a symptom of hypercapnia?

Hypercapnia, which refers to an elevated level of carbon dioxide in the blood, can lead to several symptoms due to the body's response to increased CO2 levels. Loss of consciousness is a significant symptom associated with hypercapnia. When carbon dioxide concentrations become too high, it can disrupt the normal balance of gases in the body and result in respiratory acidosis—this condition affects the central nervous system and can lead to confusion, dizziness, and ultimately loss of consciousness if the levels are not managed.

Other symptoms of hypercapnia may include headache, flushed skin, and shortness of breath, but the loss of consciousness represents a more critical and severe manifestation of the condition, indicating that the body is experiencing significant distress due to the elevated CO2 levels.