In multicellular or metazoan organisms, cells are grouped together to allow organic functioning. Metazoans can be invertebrates or vertebrates.
Invertebrates are divided into:
Spongiaria: spongesCelenterates: jellyfish and polypsEchinoderms: sea urchins and starfishPlathelmites: tapewormsNemathelminths: ascaridsRinged: marine worms, earthwormsArthropods
a) insects: bees, flies, mosquitoes
b) crustaceans: prawns, shrimps
c) arachnids: spiders, scorpions
d) myriapods: centipedes Molluscs: snails, octopuses, mussels