What is the primary role of antibodies in the immune system?

Antibodies play a crucial role in the immune system primarily by neutralizing pathogens such as bacteria and viruses. They are proteins produced by B cells that specifically recognize and bind to antigens, which are foreign substances that trigger an immune response. When antibodies bind to these antigens, they can neutralize the pathogen directly or mark it for destruction by other components of the immune system, such as phagocytes and complement proteins.

This ability to specifically identify and target pathogens is essential for the body's defense mechanisms, allowing it to respond effectively to infections and reducing the likelihood of illness. The process of neutralization can block the pathogen’s ability to enter or damage our cells, effectively rendering it harmless.

In contrast, the other options pertain to different biological functions that do not relate to the primary role of antibodies in the immune response. Transporting oxygen is primarily the function of hemoglobin in red blood cells, providing cellular energy is related to metabolic processes mainly involving adenosine triphosphate (ATP), and regulating body temperature is a physiological process managed by various systems in the body, primarily the hypothalamus. These functions illustrate the diverse roles various molecules and systems play in supporting life, but they do not encompass the specific duty of antibodies in immunology