Oddly enough, type O blood in the U.S. is not by itself the rarest blood type. Actually O+ is one of the most common. But because O is the recessive of the A-B-O gene group, and also Rh- is recessive in it's gene, the combination makes it extremely rare. Roughly 85% if people have the Rh+ allele, and roughly 1/3 people are O, but those are only O+.
The rarest is actually AB-, because 3% or less are this type. O- people are around 5% of population.
However because O- blood is the "universal donor" (will not cause immune reactions with any other blood type when transfused in) for hospitals and blood banks, it is always in short supply.
Is this a multiple choice question?
You would want to know early on if deadly disease runs in your family, because it may be hereditary, and you will have an increased risk of obtaining the deadly disease, due to your family history and gene traits.
Connections Academy?
And, It's important because you might hurt someone's feelings. Or you can appear to be disrespectful, even if you're not trying to be. Avoid using all caps because apparently that is seen as "yelling." And be sure to use "clean words" refrain from cursing :) obviously.
