What is a primary function of antibodies?

Antibodies play a crucial role in the immune system by binding to specific antigens, which are foreign substances such as pathogens or toxins that can trigger an immune response. When antibodies bind to these antigens, they facilitate pathogen clearance through various mechanisms, including neutralization, opsonization, and activation of the complement system. This process helps the body to identify and eliminate invading organisms more effectively.

In addition to directly neutralizing pathogens, antibodies can also mark them for destruction by other immune cells. This engagement is essential for the immune system to function properly, ensuring that infections are cleared and the body is protected from disease.

The other options, while related to physiological processes, do not describe a primary function of antibodies. Antibodies do not reproduce; that function is performed by immune cells such as B cells. They also do not manage electrolyte balance or produce hormones; those are tasks handled by other systems and components within the body. Thus, identifying the primary function of antibodies as binding to antigens and facilitating pathogen clearance highlights their essential role in maintaining immune defense.