What are the main components of blood?

The main components of blood include red blood cells, white blood cells, platelets, and plasma.

Red blood cells, or erythrocytes, are responsible for transporting oxygen from the lungs to the body's tissues and returning carbon dioxide from the tissues back to the lungs. They contain hemoglobin, a protein that binds oxygen. White blood cells, or leukocytes, are crucial for the immune response, helping the body fight infections and diseases. Platelets, or thrombocytes, are small cell fragments that play a key role in blood clotting, which prevents excessive bleeding when injuries occur. Lastly, plasma is the liquid portion of blood that carries these cells, along with nutrients, hormones, electrolytes, and waste products.

This choice encompasses the comprehensive understanding of blood's functionality and its essential components, highlighting their distinct roles within the circulatory system. Other options presented do not reflect the correct components of blood, as they pertain to different biological systems or tissues.