An antibody is any substance capable of triggering an immune response

The statement is not entirely accurate. An antibody is a protein produced by the body's immune system when it detects harmful substances, known as antigens. Antibodies play a crucial role in the immune response by recognizing and binding to specific antigens, such as viruses or bacteria, which helps to neutralize or destroy them. However, it's not the antibody that triggers the immune response, but the antigen. The antigen, which can be a bacteria, virus, or other foreign substance, enters the body and triggers the immune response, leading to the production of antibodies.