On which side of the body is the notochord located in chordates?

In which of the following,the notochord is replaced by a vertebral column in the adult stage?

Which of the following is described as a protochordate?

Which of the following is not a characteristic of chordates?

Select the correct statements with reference to chordates.
$A$. Presence of a mid-dorsal,solid and double nerve cord.
$B$. Presence of closed circulatory system.
$C$. Presence of paired pharyngeal gill slits.
$D$. Presence of dorsal heart.
$E$. Triploblastic pseudocoelomate animals.
Choose the correct answer from the options given below:

Which of the following animals is included in Urochordata?