Correct Option
The blood typically contains a significantly higher number of platelets compared to white blood cells (WBCs). A normal adult's blood usually has approximately 150,000 to 450,000 platelets per microlitre, while the WBC count ranges from about 4,000 to 11,000 per microlitre. Platelets are crucial for blood clotting, whereas WBCs are integral to the immune system.
Incorrect Options
A: Veins are generally more numerous than arteries and serve as a major blood reservoir, holding a larger proportion of the body's total blood volume at any given time. Arteries primarily distribute blood under high pressure.
B: Blood cells (red blood cells, white blood cells, and platelets) constitute approximately 40-45 percent of the total blood volume. This percentage is known as the hematocrit. The remaining 55-60 percent is plasma, the liquid component of blood.
C: White blood cells (leukocytes) are primarily produced in the bone marrow. While lymph nodes and other lymphoid organs play a vital role in the maturation, storage, and activation of certain types of WBCs, they are not the sole or primary site of WBC production.