Which of the following character is presence essentialy in chordates ?
Ventral spinal chord
Dorsal heart
Pharyngeal gill slits
Blood flow in forward direction in ventral blood vessels
C.
Pharyngeal gill slits
Chordate animals at some time in their life history exhibit the following three diagnostic characters
(1) Presence of notocnord.
(2) Presence of dorsal tubular nerve cord.
(3) Presence of gill clifts during development
Beside these some other characters are :
(a) ventral heart
(b) Hepatic portal system.
Which of the following is not found in Hydra ?
Epithelio-muscular cells
Cnidocyte
Choanocyte
Nerve cells
Class Crustacea differ from Insecta in having:
two pairs of antennae
jointed foot
chitinous cuticle
none of these