Which of the following statements is true regarding the materials that make up the buffy coat in centrifuged blood?

• A. The buffy coat is composed primarily of erythrocytes.
• B. The buffy coat consists only of plasma.
• C. The buffy coat is made up of dissolved nutrients and hormones.
• D. The buffy coat contains leukocytes and platelets.

Answer: (D)

Verified step by step guidance

1. Understand the composition of whole blood, which includes plasma, erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.
2. Recall the process of centrifugation of blood, which separates blood into layers based on density: the bottom layer contains erythrocytes, the top layer is plasma, and the middle thin layer is the buffy coat.
3. Identify that the buffy coat is the thin layer between plasma and erythrocytes after centrifugation, and it contains the less dense cellular components compared to erythrocytes.
4. Recognize that the buffy coat is primarily composed of leukocytes and platelets, not erythrocytes or plasma, nor dissolved nutrients and hormones.
5. Conclude that the correct statement is that the buffy coat contains leukocytes and platelets, distinguishing it from the other options.