What type of blood cells are involved in defending the body against infections?

Leukocytes, also known as white blood cells, play a crucial role in the body's immune response. They are responsible for identifying and attacking pathogens, such as bacteria and viruses, which cause infections. There are several types of leukocytes, including lymphocytes, neutrophils, and monocytes, each with specific functions in the immune system. Their primary responsibility is to protect the body from infections and foreign invaders, making them vital for maintaining health and preventing disease.

In contrast, erythrocytes, or red blood cells, are primarily responsible for transporting oxygen from the lungs to the body's tissues and returning carbon dioxide for exhalation. Platelets and thrombocytes refer to the same component of blood that is essential for blood clotting but are not directly involved in fighting infections. Therefore, leukocytes are definitively the blood cells tasked with defending the body against infections.