What is the primary component of plasma in blood?

The primary component of plasma in blood is water, which constitutes about 90% of its volume. Plasma, the liquid portion of blood, serves several critical functions, including transporting nutrients, hormones, and waste products throughout the body. The high water content allows for effective transport of these substances, as it provides a fluid medium through which various components can dissolve and circulate. The proteins in plasma, while significant and essential for functions such as blood clotting and immune responses, make up a smaller percentage of its composition compared to water. Thus, the dominant composition of plasma by volume is indeed water, which supports maintaining blood pressure and regulating body temperature.