CPR is a series of life saving actions that improve the chances of survival following.

cardiac arrest

Explanation:

when someone is in cardiac arrest the best way to save them is doing CPR on them and that will help with the heart to start pumping blood again to lungs and to the brain

hope this helps

it's 150 100% postive

depends where it is? i got mine on my arm and from 1-10 it was a 3 different spots react differently