What are facts about the circularity system?

Answer 1

=The human heart beats between 60 & 100 beats per minute. In that minute the 6 liters of blood travels, once, all the way around the body.==There are 60,000 miles of blood vessels in the human body.==Woman's hearts beat faster than men's.==An individual blood cell takes about 60 seconds to make a complete circuit of the body.==Each square inch of human skin consists of twenty feet of blood vessels.==It would take 1,200,000 mosquitoes, each sucking once, to completely drain the average human of blood.==The most common blood type in the world is Type O. The rarest, Type A-H, has been found in less than a dozen people since the type was discovered.==There are four main Blood types: A, B, AB and O and each Blood type is either Rh positive or negative. Blood types in the US - Type O positive 38.4%, O negative 7.7%, A positive 32.3%, A negative 6.5%, B positive 9.4%, B negative 1.7%, AB positive 3.2%, AB negative 0.7%=