What are the approximate percentages of cells and plasma in blood?

• A. 50% and 50%, respectively
• B. 30% and 70%, respectively
• C. 60% and 40%, respectively
• D. 40% and 60%, respectively

Answer: (D)

Blood consists of plasma and formed elements. Plasma is the liquid portion, making up about 60% of blood, while the formed elements—red blood cells, white blood cells, and platelets—account for about 40%. This distribution reflects the hematocrit, which is typically around 40–45% in many species, with plasma occupying the remainder. While exact values vary by species and hydration, the general rule is roughly 40% cells and 60% plasma, so that option fits best.