PATHOLOGY

Detailed explanation-1: -White blood cells are immune system cells. They are like warriors waiting in your blood stream to attack invaders such as bacteria and viruses. When fighting an infection, your body produces more white blood cells.

Detailed explanation-2: -Your immune system works hard to keep you healthy. Its job is to keep germs out of your body, destroy them or limit the extent of their harm if they get in.

Detailed explanation-3: -The innate immune system. You are born with this. The adaptive immune system. You develop this when your body is exposed to microbes or chemicals released by microbes.