Class Crustacea differ from Insecta in having:
two pairs of antennae
jointed foot
chitinous cuticle
none of these
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
Which of the following is not found in Hydra ?
Epithelio-muscular cells
Cnidocyte
Choanocyte
Nerve cells
Which of the following symmetry is found in adult sea-anemone ?
Radial
Biradial
Bilateral
Spherical
All worms are :
triploblastic
segmented
endo-parasites
free - living
A.
triploblastic
All worms which belongs to phylum Platyhelminthes and Aschelminthes are triploblastic i.e. body is composed of three primary germ layers, namely, ectoderm, mesoderm and endoderm. These may be either endo-parasites or exo-parasites and generally devoid of body segmentation.
Pearl oyster is a mollusc which belongs to class :
Cephalopoda
Pelecypoda
Scaphopoda
Gastropoda