Final answer:
The body responds to dehydration by increasing fluid intake and retention through mechanisms such as the release of ADH and stimulation of thirst. The kidneys also increase the production of EPO to increase blood volume.
Step-by-step explanation:
Dehydration triggers several bodily mechanisms to increase fluid intake and retention. When the body becomes dehydrated, the hypothalamus releases antidiuretic hormone (ADH), which signals the kidneys to recover water from urine, effectively diluting the blood plasma. The hypothalamus also stimulates the thirst response, prompting the person to drink water. Additionally, the kidneys increase the production of erythropoietin (EPO), which stimulates the formation of red blood cells and increases blood volume.