What are antibodies?

Antibodies are specialized proteins that play a crucial role in the immune system by identifying and neutralizing foreign objects such as bacteria and viruses. When the body detects an invader, B-cells, a type of white blood cell, produce antibodies that specifically target that invader. Each antibody is designed to bind to a specific antigen, which is a substance that prompts the immune response. This binding effectively marks the pathogens for destruction by other immune cells or neutralizes them directly, preventing them from causing harm.

The other options describe different biological components: red blood cells carry oxygen; enzymes are molecules that accelerate chemical reactions; and hormones are signaling molecules that regulate various physiological functions. Understanding antibodies and their role in immunity is critical for recognizing how the body defends against infections and diseases.