The skin is an example of a non-specific defense.
For example, bacteria or diseases have trouble entering a healthy person's skin because it is formed by closely packed cells with multiple layers and a substance called keratin that protects is.
On the other hand, the immune system is a specific defense mechanism.
When bacteria is able to enter the body in cases of fever for example, the immune system is activate and sends out protector cells such as the white blood cells to combat infection.