The reason blood is so incredibly efficient is that our red blood cells are not dedicated to specific organs or tissues; otherwise, we would probably have traffic jams in our veins.
Razlog zbog kojeg je krv toliko učinkovita je taj što naše crvene  krvne stanice ne idu određenim organima ili tkivima; u suprotnom bi vjerojatno imali  prometne gužve u venama.