The immune system is a network of cells, tissues, and organs that work together to defend the body from harmful germs. When bacteria, viruses, and other germs invade your body, they multiply and attack. This invasion is called an infection. Infections cause the diseases that make you sick.

Your immune system protects you from the disease by fighting off the invading germs.

• Biological Structures and processes
• Protects against disease
• It is a layered system providing differing levels of protection
• There are 3 lines of defence