Which of the following is a common sign of dehydration?

Dry mouth is a common sign of dehydration because it occurs when the body lacks sufficient fluids to maintain proper moisture levels in the mouth and throat. When dehydration starts to develop, the salivary glands produce less saliva, leading to a dry or sticky feeling in the mouth. This symptom is often one of the earliest indicators that the body is becoming dehydrated, as the mouth is highly sensitive to changes in hydration status. Recognizing a dry mouth is important for early intervention to prevent further dehydration and its associated health risks.

In contrast, increased appetite typically does not relate to dehydration, as the body may actually signal for a need for fluids rather than food. Low energy can result from many conditions, including dehydration, but it is a more general symptom and not exclusively signifying fluid imbalance. Frequent urination may not be indicative of dehydration either; in fact, it can sometimes lead to fluid loss, but dehydration is more often characterized by reduced urination.