Which of the following animals is known as an invertebrate chordate?

Observe the following simplified scheme of the division $Vertebrata$ and choose the correct option that matches with the letters given in the boxes.
$Vertebrata$ (Division)
- $p$ (Lacks jaw)
- $q$ (Bears jaw)
- Super class
- $r$ (Bear fins)
- $s$ (Bear limbs)

The notochord is derived from which of the following germ layers?

By which developmental similarity are Echinoderms related to Chordates?

Which of the following statements is/are correct for the phylum Chordata?
$(a)$ In Cephalochordata,the notochord extends from head to tail region and is persistent throughout their life.
$(b)$ In Vertebrata,the notochord is present only during the embryonic period.
$(c)$ The central nervous system is dorsal and hollow.
$(d)$ Chordata is divided into $3$ subphyla: Hemichordata,Urochordata,and Cephalochordata.

Which one of the following features are true for chordates?
$(a)$ Heart is ventral.
$(b)$ Pharyngeal gill slits present.
$(c)$ Central nervous system is ventral,solid and single.
$(d)$ Post-anal tail is present.
$(e)$ Notochord is present.
Choose the most appropriate answer from the options given below: