Final answer:
The formed elements in blood are red blood cells, white blood cells, and platelets. Erythrocytes carry oxygen, leukocytes fight against pathogens, and platelets promote clotting and healing.
Step-by-step explanation:
The formed elements in blood are the red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Erythrocytes are the most abundant cells in the blood and are responsible for carrying oxygen to the body's tissues. They contain a pigment called hemoglobin which binds to oxygen in the lungs and releases it in the tissues.
Leukocytes are involved in the immune response and help fight against pathogens and diseased cells. They can leave the blood vessels to reach the site of infection or attach to organs to eliminate threats to health. Platelets are cell fragments that are essential for blood clotting and promote repair and healing.