Approximately what percentage of blood is made up of water?

The correct answer is that approximately 90% of blood is made up of water. Blood consists of various components, and the most significant portion is plasma, which is largely water. Plasma alone accounts for about 55% of the total blood volume, and since plasma is predominantly water, this contributes significantly to the overall composition of blood.

Understanding the high water content of blood is crucial for several reasons. Water plays a vital role in maintaining blood viscosity, regulating body temperature, and transporting nutrients and waste products throughout the body. Hydration is essential for optimal blood volume and circulation, impacting athletic performance and overall health.

The other choices indicate lower percentages of water in blood, which do not accurately reflect the high water content that supports its crucial physiological functions. This highlights the importance of proper hydration for athletes and individuals looking to maintain their health and performance.