Differentiate between Platyhelminthes and Aschelminthes.
(b) Annelida and Arthropoda
(c) Mollusca and Echinodermata

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Please find below the solution to the asked query    
          

a. 

Platyhelminthes	Aschelminthes
Include flatworms	Include roundworms
Hermaphrodites	Sexes are separate
No respiratory organ	Skin acts as respiratory organ
Development is either direct or indirect	Development is direct

b. 

Annelida	Arthropoda
They do not have any distinct head.	Their body is differentiated into head, thorax and abdomen.
Exoskeleton is absent.	Body is covered by chitinous exoskeleton.
Locomotion is done by setae, parapodia or suckers.	Three pairs of jointed appendages are present for locomotion.
Respiration occurs through skin.	Respiration occurs through trachea or book lungs.
E.g. Earthworm, Leech	E.g. Cockroach, Spider

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