Usually,chordates have red blood containing red blood corpuscles. The blood is red due to the presence of the following pigment:

Which of the following is $NOT$ a subphylum of Phylum $Chordata$?

Select the correct option for Non-chordates:
$(I)$ Central nervous system is ventral,solid,and double
$(II)$ Gill slits are absent
$(III)$ Heart is ventral
$(IV)$ Post-anal tail is absent

Cephalochordates are ..........

Give three major differences between chordates and non-chordates and draw a schematic sketch of a chordate showing those features.

Besides $Annelida$ and $Arthropoda$,metamerism is found in