Answer:
so we can move our back and be flexible
Explanation:
brainliest?
60 years is three half life for the substance, so 40*1/2^3=5
If blood typing is not available in an emergency situation, O-Negative blood is universally accepted by all blood types because it is absent of any antibodies. Therefore, if O-Neg blood is on hand in emergency situations, it can be given to anyone.