What is the primary role of white blood cells in the immune response?

White blood cells, also known as leukocytes, play a crucial role in the immune response primarily by recognizing and eliminating pathogens that can cause infections. This function is vital for maintaining the body's health and defending against various diseases. Different types of white blood cells have specialized roles; for instance, lymphocytes (which include T cells and B cells) are key in identifying and targeting specific pathogens, while phagocytes engulf and digest harmful microorganisms and debris.

The recognition of pathogens involves various mechanisms, such as the presentation of antigens (parts of an invading organism) that help the immune system identify and respond to the threat effectively. Once recognized, white blood cells can mount an appropriate response, either by directly attacking the pathogens or by coordinating a broader immune response involving other cells and proteins.

The other options outlined do not pertain to the primary function of white blood cells. Transporting oxygen is primarily the role of red blood cells, regulating blood pressure involves other cellular and physiological mechanisms, and the formation of blood clots is primarily managed by platelets and clotting factors, not white blood cells. Therefore, the core responsibility of white blood cells is indeed centered around recognizing and eliminating pathogens, making this the correct choice.