What are the signs of decompression sickness?

The correct answer, which identifies joint pain and breathing difficulties as signs of decompression sickness, highlights key symptoms associated with this condition. Decompression sickness can occur when a diver ascends too quickly, causing nitrogen bubbles to form in the body due to rapid changes in pressure. These bubbles can accumulate in various tissues and joints, resulting in significant pain, especially in the arms and legs, commonly referred to as "the bends." Additionally, as these bubbles may affect the lungs, divers can experience breathing difficulties, which can lead to serious complications if not addressed promptly.

In contrast, the other options list symptoms that do not relate to decompression sickness. Excessive energy and clarity of vision could be mistakenly perceived as positive indicators, but they are not associated with the physiological impacts of decompression illness. Increased heart rate and numbness may also occur in different contexts but are not specific indicators of decompression sickness. Similarly, improved buoyancy control is unrelated to decompression sickness and does not represent any physiological signs of the condition. Understanding these symptoms is critical for divers to recognize and respond appropriately to potential decompression issues.