Kingdom Animalia

Answer (b) True coelom

Shell fish are edible aquatic invertebrates, including various species of molluscs, crustaceans and echinoderms.

Answer (d) Amphibians

Answer (c) Arthropoda

Answer (b) Earthworms

Answer (d) Gastrovascular cavity

Hepatopancreas is an excretory organ of some arthropods (invertebrates) e.g. scorpion.

Answer (b) Beroe

Star fish or sea star is an echinoderm. Clam worm is an annelid whereas apple snail is a mollusc. Silver fish, prawn, honeybee, tongue worm, scorpion and cockroach are arthropods.

Incisors are the front teeth borne by the premaxillae in upper jaw and tips of dentaries in lower jaw. They are single-rooted, monocuspid and long, curved and sharp-edged. They are adapted for seizing, cutting and biting. Elephant tusks are modified upper incisors with open roots.

Ostia are the pores present in the body wall of poriferans (sponges). Through ostia, the water moves in and out of the body of sponges.

Notochord persists throughout life in the lower chordates, but in the higher chordates, it is surrounded or replaced, partly or fully, in the adult by a jointed vertebral column. In urochordata, notochord is present only in larval tail, while in cephalochordata (Amphioxus), it extends from head to tail region and is persistent throughout their life.

Setae and parapodia are locomotory structures in annelids. Except leeches, unjointed chitinous setae are often present. Some annelids such as Nereis have unjointed, locomotory structures, the parapodia (para-parallel, podia
- feet).
The leech bears two suckers. The anterior sucker encloses the mouth. It acts as a feeding, locomotory and prehensile organ. The posterior sucker lies at the hinder part of the body.

Chordates differ from non-chordates in having notochord, dorsal hollow nerve cord and pharyngeal gill slits

All existing echinoderms are marine. They generally live at sea bottom. Some are pelagic and a few are sessile.

Answer (c) Fishes