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
Pearl oyster is a mollusc which belongs to class :
Cephalopoda
Pelecypoda
Scaphopoda
Gastropoda
B.
Pelecypoda
Pinctada is commonly called Indian pearl oyster. Oyster's shell secretes pearls, whenever any organism enters the shell and causes irritation. Pinctada belongs to Phylum-Mollusca and Class Pelecypoda.