Which blood group is the worlds Rarest Blood grup

Are the earth's ocean floor and continents the same age geologically? why or why not?

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen

To maintain asepsis when administering an injection, all parts of the syringe can be handled except the: