That's CORRECT!!

The immune system defends the body against
any infectious organisms that attack the body. Your white
blood cells are very important for your body to try to
protect itself. Without this system, our bodies would
get sick from all of the bacteria and infections
that attack our bodies every day.
For further detail about the immune system you
can look at the following links provided:
Immune System
Overview of the Immune System
Let's CONTINUE on our journey
through the systems of the body.