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

The body is divided into head and trunk in:

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:

To which group does $Salpa$ belong?

The wheel organ is found in:

Definition / Explanation: Notochord