What is the name of the protein molecule that destroys bacteria or viruses?

The protein molecule that destroys bacteria or viruses is known as an antibody. Antibodies are specialized proteins produced by the immune system in response to pathogens, like bacteria and viruses. When these foreign invaders enter the body, the immune system recognizes them as threats and generates antibodies specifically designed to bind to those pathogens. This binding can neutralize the pathogens directly or mark them for destruction by other immune cells.

Antibodies play a crucial role in adaptive immunity, which is the body's tailored immune response that enhances with exposure to specific pathogens. They are also significant in various medical applications, including vaccines, which stimulate the production of antibodies to build immunity against certain diseases.

Other options provided, such as enzymes, hormones, and antigens, have distinct functions in the body. Enzymes are biological catalysts facilitating chemical reactions, hormones are signaling molecules regulating various physiological processes, and antigens are substances that trigger the immune response. However, it is the antibody that specifically targets and neutralizes harmful microbes, which is why it is the correct answer.