What is the major function of white blood cells?

The major function of white blood cells, also known as leukocytes, is to protect the body against infections. They are a key component of the immune system, which is responsible for identifying and combating pathogens such as bacteria, viruses, and parasites. White blood cells can detect foreign invaders, initiate an immune response, and either directly attack the pathogens or produce antibodies to mark them for destruction by other immune cells.

This protection is essential for maintaining overall health as it enables the body to respond effectively to infections and diseases. The different types of white blood cells, including lymphocytes, neutrophils, monocytes, eosinophils, and basophils, play varied roles in the immune response, ranging from attacking and consuming pathogens to coordinating the immune reaction.

In contrast, the other options do not accurately reflect the primary role of white blood cells. Transporting carbon dioxide to the lungs is a function associated with red blood cells, assisting in oxygen transport is also primarily the role of red blood cells, and regulating blood glucose levels involves hormones like insulin rather than the actions of white blood cells.