Answer:
The immune system works to keep germs out of the body and destroy any that get in. The immune system is made up of a complex network of cells and organs that protect the body from infection. Lymph nodes are part of the immune system. They release lymphocytes, a certain type of white blood cell that fights infection.
Explanation:n . Hope this helps .
The result of poor cardio respiratory endurance is Heart disease
By showing them the effects on your body
If there were a fire, explosion, or bomb threats in schools, for example, are required to evacuate but if it's a sniper or shooter then they do a lockdown. Because if the shooter is on the outside and they decide to evacuate then they could get shoot so most schools and places do lockdowns.
So the answer would be a sniper. I hope this helps!