What are the names given to the body's first and second line of defence against disease? Name an example for each and how it works to prevent disease.

The first line of defence is passive immunity. An example is the skin and its job is to prevent a pathogen entering the body in the first place. Pathogens cannot penetrate the skin. The second line of defence is known as active immunity. An example is white blood cells and it prevents disease by ingesting pathogens to destroy them. They can also produce antibodies and antitoxins.