What are the three body regions of most arthropods?
Body regions of arthropod organisms are :
In organisms like spider or scorpion:
there are prosoma (head plus thorax) and opisthosoma (abdomen).
In organisms like centipede and millipede:
there are head and trunk (thorax plus abdomen).
In aquatic crustaceans:
there are cephalothorax (head plus thorax) and abdomen.
In six legged insects, all three parts are distinct. Insects are also the most abundant class of phylum arthropoda.