(N/A) The three major differences between chordates and non-chordates are as follows:
$1$. Notochord: Chordates possess a notochord at some stage of their life cycle,whereas non-chordates lack a notochord.
$2$. Central Nervous System: In chordates,the central nervous system is dorsal,hollow,and single. In non-chordates,it is ventral,solid,and double.
$3$. Pharyngeal Gill Slits: Chordates exhibit pharyngeal gill slits at some stage of development,which are absent in non-chordates.
Schematic sketch description: $A$ chordate body plan includes a dorsal hollow nerve cord,a notochord located below the nerve cord,a post-anal tail,and pharyngeal gill slits in the pharyngeal region.