What do antibodies do?

Antibodies play a crucial role in the immune system by specifically recognizing and binding to antigens, which are foreign substances such as bacteria, viruses, or toxins that can provoke an immune response. When antibodies attach to these antigens, they can neutralize their harmful effects directly. This binding can also mark the antigens for destruction by other immune cells, enhancing their clearance from the body. This mechanism is a fundamental aspect of the adaptive immune response, allowing the body to recognize and respond to pathogens more effectively over time.

The other choices do not accurately describe the function of antibodies. Antibodies do not stimulate the immune system to produce antigens, nor do they function as enzymes in digestion. Additionally, they do not act as filters for waste products in the blood; this is a role fulfilled by the kidneys and other organs. Therefore, the primary and distinctive role of antibodies is to attach to and neutralize antigens, making the selection of this answer the most accurate representation of their function in the immune system.