Animal Classification: Invertebrates and Vertebrates

Starfish belongs to the phylum Echinodermata, which has a water vascular system for locomotion, transportation of food and respiration.

Both the statements are correct.
Option 4 is correct.

True metamerism is found in annelids and arthropods.

Balanoglossus belongs to phylum Hemichordata, which has an excretory organ known as proboscis gland.

Aves or birds have an oil gland at the base of the tail.

All the cavities in a sponge's body are intercommunicating and are collectively referred to as the canal system. Thus, the canal system helps the sponge in nutrition, respiration and excretion.

A flexible tongue-like organ in certain mollusks, having rows of horny teeth on the surface, used for rasping food

Choanocytes are flagellated cells lining the body cavity of a sponge.

Hemocoelic or blood-filled body cavity is a characteristic of arthropods, e.g. scorpion.

Bioluminescence is a characterstic feature of phylum ctenophora.

Polyp and medusa - names for the two body forms, one non motile and one typically free swimming, found in the aquatic invertebrate phylum cnidaria.

Scolex is the frontal segment of a tapeworm, having suckers or hooks for attaching to the host.

In some flatworms, the process of cephalisation includes the development in the head region of light-sensitive organs called ocelli or eye spots. For example, planaria.

Malpighian tubules or green glands are the excretory organs of arhropods.

Sea horse or hippocampus is a bony fish.