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

The main role of antibodies in the immune system is to identify and neutralize pathogens. Antibodies, also known as immunoglobulins, are specialized proteins produced by B cells in response to foreign substances, such as bacteria, viruses, and toxins. They bind specifically to antigens on these pathogens, marking them for destruction by other immune cells or neutralizing their harmful effects. This binding can lead to various immune responses, including agglutination, opsonization, and complement activation, enhancing the immune system's ability to eliminate infections.

While other choices refer to various functions in the body, they do not pertain directly to the immune action performed by antibodies. For instance, transporting oxygen in the blood is primarily the function of hemoglobin, while stimulating red blood cell production is mainly regulated by erythropoietin. Promoting inflammation is a part of the immune response, but it is not directly the role of antibodies; instead, it involves signaling molecules like cytokines. Thus, identifying and neutralizing pathogens remains the specific and crucial role of antibodies in the immune system.