Question

An animal that does not perform locomotion is
A. Euglena
B. Nereis
C. Sycon
D. Sepia

Answer 1

Hint: In ethology, animal locomotion is one of a number of strategies used by animals to travel from one position to another. Some forms of locomotion, such as running, swimming, jumping, flying, walking, soaring and gliding, are self-propelled.

Complete answer:
In shallow water, Sycon is a marine sponge widely distributed. It is typically found attached to shells, stones and is sedentary. In temperate areas, they mostly harbour. Sycons lead a solitary/colonial life. These marine entities, such as shells and rocks of corals and molluscs, are found attached to the strong substratum. Within this genus, different species of sponges do not have the tendency to prosper deeper in the water. In slow-wave activity and low tides, Sycons appear to survive well. They are found among hydroids, bryozoans, and other entities on the underside of rocks in comparatively protected regions. Some emerge as marine algae, too.

Sycon (Scypha) is a sponge and locomotion is not carried out. It is a genus belonging to the family of calcareous sponges-Scolytidae, Class-Calcarea and Phylum-Porifera. These sponges are tiny and have a total length of up to 5 cm and are tube-shaped and mostly white to cream in colour.

Under the Kingdom of Protista, Euglena belongs to the Euglenophyta Group. Euglena is a motile organism that travels with the aid of flagella. Nereis belongs to the Annelida phylum and has a parapodia for locomotion.
Sepia, also known as cuttlefish, is part of the Mollusca Phylum. It has locomotion fins.

Sycon ciliatum is creamy yellow in colour and delicate-looking. Their bodies are arranged in an asconoid structure, a simple tube with no folding of the outer wall of the body. They vary in height from 1-3cm. Hairy, needle-like spines (called spicules) cover the body. The spicules around the opening of the osculum are longer than those at the base of the body.
The supporting skeleton of the sponge is created by Y-shaped tetraxon calcite spicules lining the spongocoel and the triactin spicules in the walls of the flagellate chambers. The spicules tend to lie in a jelly called mesohyl, a structural jelly comprising archaeocytes, amoeboid cells, and others.

Hence, the correct answer is option (C)

Note: Sycon ciliatum can tolerate water movements and shifts in tides. The hair-like coating of the calcite spicules retains water for capillary action. This also prevents air from entering the chambers. As with all aquatic life, Sycon ciliatum is affected by water pollution, temperature variations and changes in water levels.