Bacteria is something else that you would need to know
A). If you get sick, you have a weakness within the immune system that causes you to have the symptoms of the illness as the white blood cells are failing in getting rid of the illness itself.
B. Spinal nerves I think, it makes most sense to me.
Epithelial cells is the type of tissue that is designed to regulate temperature, secrete lubricants, and protect the body from harmful substances. Hope this helped! :)
If there is no response and not breathing or not breathing normally, position the infant on his or her back and begin CPR. Give 30 gentle chest compressions at the rate of 100-120/minute. Use two or three fingers in the center of the chest just below the nipples.
source :CPR Instructions For Infants and Small Children
depts.washington.edu/learncpr/infantcpr.html