Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       particles
         elementary particles
           elementary fermions - elementary particles with half-integer spin
             antiquarks
               1.1 antiup quark
               1.2 antidown quark
               2.1 antistrange quark
               2.2 anticharm quark
               3.1 antibottom quark
               3.2 antitop quark