| Your immune system helps to protect you against viruses and bacteria that can cause sickness. Which cell is a part of immune system? |
| a) | White memory | b) | Red blood T-cells |
| c) | Nerve cells B-cells | d) | All of the above |
| (a)WBCs (Polymorpho-nuclear leukocytes and monocytes, natural killer lymphocytes) and macrophages, phagocytose and destroy microbes |