Which of the following are signs of dehydration?

Dehydration occurs when the body loses more fluid than it takes in, which can lead to a variety of symptoms that indicate the body needs more hydration. The signs listed in the correct answer prominently include thirst, dry mouth, fatigue, and dizziness.

Thirst is the body's immediate response to dehydration, signaling that more fluids are needed. A dry mouth is a clear physical indication that saliva production has decreased due to insufficient fluid intake. Fatigue often accompanies dehydration, as the body lacks the necessary fluids to function optimally, which can lead to feelings of tiredness. Dizziness can arise when dehydration affects blood volume and circulation, resulting in lower blood pressure and reduced blood flow to the brain.

This combination of symptoms distinctly characterizes dehydration, making it crucial to recognize for timely hydration and recovery. The other options mention symptoms that can relate to a variety of conditions or are not specific to dehydration, emphasizing the importance of identifying the correct signs associated specifically with fluid loss in the body.