What does blood consist of?

Blood is composed of both cells and liquid substances. Specifically, it includes red blood cells, white blood cells, platelets, and plasma. The red blood cells are responsible for transporting oxygen throughout the body, while white blood cells play a vital role in the immune system by fighting off infections. Platelets help with blood clotting, which is crucial for healing wounds. Plasma, the liquid component of blood, serves as a medium for carrying these cells, hormones, nutrients, and waste products.

Option B encompasses this comprehensive composition of blood, making it the correct answer. Other choices focus on only specific components, neglecting the overall structure and the important roles played by each part in maintaining health and functionality in the body.