Final answer:
Fluid shifts in isonatremic dehydration occur from intravascular to extravascular, causing various physiological effects on the body. So, the correct answer is option a.
Step-by-step explanation:
Fluid shifts in isonatremic dehydration occur from intravascular to extravascular.
In this type of dehydration, the concentration of electrolytes in body fluids is maintained constant through the elimination or retention of water. The volume of body water decreases, causing intracellular edema, slower circulation, and impaired urinal function.
This fluid shift is important for maintaining homeostasis and ensuring proper cellular functions.
So, the correct answer is option a.