Outline the symptoms of nitrogen narcosis.

Nitrogen narcosis is typically characterized by a range of cognitive and physical impairments as a diver goes deeper underwater, where the partial pressure of nitrogen increases. The correct choice identifies key symptoms such as impaired judgment, euphoria, and decreased motor performance, which directly result from the narcotic effects of nitrogen at increased depths.

When divers experience impaired judgment, they may make poor decisions or engage in risky behavior that they wouldn’t normally consider. Euphoria can lead to a false sense of well-being or even invincibility, which can distract from a diver's responsibilities and safety protocols. Decreased motor performance can further complicate situations underwater, making it difficult to execute tasks such as operating equipment or responding to unexpected events.

The other options describe symptoms that do not align with nitrogen narcosis. Increased alertness and excitement are not common characteristics of this condition; rather, divers might feel relaxed or detached. Severe headaches and nausea, while potential issues in diving, are more commonly associated with other conditions like decompression sickness rather than nitrogen narcosis. Finally, confusion and shortness of breath can indicate various diving-related problems but do not specifically encapsulate the hallmark signs of nitrogen narcosis. Thus, recognizing and understanding the symptoms outlined in the