Help with biology!!?

Question

i need these following phylum in order from least complex to most complex and why their in that order

-Molluska

-Chordata

-Arthropoda

-Annelida

-Nematoda

-Platyhelminthes

-Cnidaria

-Echinodermata

I know that the first on is Cnidaria

Answer 1

cnidaria- Two way digestive tract; gastrovascular cavity; two cell layers thick with jelly-like material in between.

platyhelminthes- simple flat worm; some parasitic; triploblastic (three simple germ layers).

Nematode- "Tube within a tube" body plan. One way digestive tract. Free-living & parasitic.

Echinoderm-Radial symmetry;

Annelids- Well developed organ systems; primative nervous system.

Molluska- Well developed nervous system; Land & aquatic adaptations.

Arthropods- Well developed Ner. syst.; appentages adapted for terrestrial and aquatic life.; Greatest number of different species. Very successful. exoskeleton.

Chordata -Well developed systems; endoskeleton; relatively high intelligence

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