To the second question the answer, in short, is YES;To answer the first question, there are four logical bloodtypes: A, B, AB, and O. Then there is the Rhesus factor: eitherpositive or negative. So there are actually eight types of blood ahuman can have: one of the above types with a negative Rhesusfactor or with a positive Rhesus factor. Rhesus factor is a factorwhich compares human blood to a Rhesus monkey's blood. A negativeresult means your blood is not comparable to a Rhesus monkey.Blood types are inherited from your parents. If one parent hastype A+, and the other has a B-, your blood type can either comeout as A, + or -, or B, + or -, or the rare AB, + or - but not O.While type O negative is the universal donor, type AB positive is auniversal recipient.