Question

Which among the following is exclusively marine?

• A. Porifera
• B. Echinodermata
• C. Mollusca
• D. Pisces

Answer 1

The correct option is B

Echinodermata

The correct option is B.

Explanation of incorrect option:

1. Echinoderms are only found in marine habitats.
2. For example starfish, sea urchins, and other species are found on the seabed and in deep oceans.
3. They have a unique water circulatory system that allows them to survive in a saline environment.
4. They do not exist in freshwater or on land.

Explanation of incorrect options:

Option A:

1. Porifera is found in both fresh water and marine habitat.
2. e.g. Haliciona and Spongilla

Option C:

1. Invertebrates belong to the phylum Mollusca.
2. Molluscs are the biggest marine phylum.
3. They also live in freshwater and terrestrial species.

Option D:

1. They are cold-blooded organisms that are poikilothermous in nature.
2. They are found in marine and freshwater.
3. Some marine fishes also migrate from marine habitats to freshwater for food and spawning.

Final answer: Echinodermata is exclusively marine.