Why must plasma liquid in which red blood cells are found) have the same water concentration as red and white blood cells?

The plasma liquid must have the same water concentration as red and white blood cells to maintain osmotic balance, preventing cell shrinkage or swelling. If the concentration differs, it can lead to osmotic pressure changes that may disrupt cellular functions, potentially causing damage or cell lysis. This balance is crucial for maintaining overall homeostasis in the bloodstream and ensuring proper physiological function.