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.
the statistics show that the rate of this increaced
Answer:
True, muscles can shrink and grow
The two upper parts of the heart are the atriums and the bottom are the ventricles.
