What type of white blood cells are known as leukocytes and protect the body against infection?

The choice of white blood cells as the correct answer is grounded in the fundamental understanding of the immune system and blood components. White blood cells, or leukocytes, are a crucial part of the body's defense mechanism, playing a vital role in identifying and combating pathogens, such as bacteria and viruses. They are not just one type of cell; rather, they encompass various cell types with distinct functions, including lymphocytes, monocytes, and granulocytes.

Granulocytes, which is another option, are a specific category of white blood cells that includes neutrophils, eosinophils, and basophils, all of which contribute to the immune response. However, the term "white blood cells" provides a broader category that includes both granulocytes and other types of leukocytes.

Erythrocytes, or red blood cells, are responsible for carrying oxygen in the bloodstream and do not play a role in protecting the body from infection. Similarly, platelets are involved in blood clotting and do not assist in fighting infections.

Thus, the term white blood cells encompasses all leukocytes tasked with defending the body against infections, making it the most comprehensive and accurate answer.