Question

Which one of the following features is present at some stage in the life history of all chordates ?

• A. blood flowing forward in dorsal blood vessel
• B. pharyngeal gill slits
• C. a ventral hollow nerve cord
• D. heart lying dorsally

Answer 1

Answer: (B)

Chordate animals, at some time intheir life history, exhibit the following three diagnostic characters.
(i) Presence of notochord.
(ii) Presence of dorsal tubular nerve cord.
(iii) Presence of gill clefts during development.
Besides these, some other characters are
(iv) Ventral heart
(v) Hepatic portal system