( a ) radially symmetrical, diploblastic and acoelomate animals with organ-system level of organisation
( b ) bilaterally symmetrical, triploblastic and coelomate animals with organ level of organisation
( c ) bilaterally symmetrical, triploblastic, segmented and coelomate animals with organ-system level of organisation
( d ) bilaterally symmetrical, diploblastic and coelomate animals with organ level of organisation
