What symptoms may indicate a person is dehydrated?

The presence of symptoms such as no tears, dry skin, and a cracked tongue aligns with the classic indicators of dehydration. These symptoms arise because dehydration leads to a reduction in the body's ability to retain moisture. When the body lacks sufficient water, it diminishes moisture production in areas like the eyes, resulting in the absence of tears. Additionally, the skin may lose its elasticity and appear dry, further reinforcing the state of dehydration. A cracked tongue implies a lack of hydration as well, indicating that the mucous membranes are not receiving adequate moisture, which can frequently occur when fluid intake is low.

The other options reflect symptoms that could potentially be linked to hydration issues but often are more ambiguous or related to other conditions. For instance, excessive thirst and increased urination can occur in various situations, including other health issues, while heavy sweating and dizziness may indicate a response to heat or exertion rather than dehydration alone. Always feeling tired could be a generalized symptom attributable to a wide range of factors and is not as specific to dehydration as the symptoms mentioned in the correct choice. Each of these other symptoms can occur alongside dehydration or may arise from separate physiological processes, making the first option the most clear-cut indicator of dehydration.