Write three characteristics each of the following groups of animals: (a) Platyhelminthes (b) Nematoda

a) Platyhelminthes :
(i) Bilaterally symmetrical
(ii) No body cavity
(iii) Dorsiventrally flattened
(iv) Flatworms / Free living or parasitic
(v) Triploblastic

(b) Nematoda :

(i) Bilaterally symmetrical
(ii) Triploblastic
(iii) Tissue level of organisation, but no real ^Organs
(iv) Pseudocoelom