A common sign of dehydration?

• A. Lethargy
• B. Extreme thirst
• C. Diarrhea
• D. Weight loss

Answer: (B)

Thirst is the body's primary signal that it needs more fluids. When hydration drops, the brain triggers the sensation of extreme thirst to prompt drinking, so this is the most common and reliable sign of dehydration. Lethargy can appear as dehydration progresses, but it isn’t as immediate or specific. Diarrhea is a potential cause or accompanying issue rather than a direct sign, and weight loss can occur with fluid loss but isn’t as quick or consistent a indicator as thirst. In practice, a strong urge to drink is the best cue to assess hydration.