Blood can be classified into two main components; what percentage is made up of plasma?

Blood is composed of two primary components: plasma and formed elements, which include red blood cells, white blood cells, and platelets. Plasma constitutes the liquid portion of the blood and plays a critical role in maintaining blood volume and pressure, transporting nutrients, waste products, hormones, and proteins throughout the body.

The correct percentage of blood that is plasma is approximately 55%. This composition reflects a typical hematocrit value, which measures the proportion of blood volume occupied by the formed elements. Understanding this percentage is essential for recognizing how blood functions and ensures that practitioners can evaluate various physiological conditions.

While the other options present percentages that could represent blood volume, they do not accurately reflect the standard composition of blood where plasma constitutes about 55%. This knowledge is fundamental for anyone studying human physiology, as alterations in these proportions can indicate various medical conditions or physiological responses.