Which of the following groups of animals are marine and characterised by a spiny skin?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Phylum Echinodermata.
- Phylum Echinodermata group of animals that are marine and characterised by a spiny skin.
- The Echinoderms are found in sea-depths as well as in the intertidal zones. An interesting feature of the phylum Echinodermata is that all the organisms belonging to this phylum are marine. None of the organisms is freshwater or marine.
- Invertebrates with pentaradial symmetry, spiny skin, a water circulatory system, and a simple nervous system are known as echinoderms.
- There are around 7,000 extant species in this phylum.
- Echinodermata are only found in the sea.
- Echinoderms include sea stars, sea cucumbers, sea urchins, sand dollars, and brittle stars.
- Echinoderms feature a calcareous endoskeleton with pentaradial symmetry and pigment cells that give them a wide spectrum of hues, as well as cells that contain poisons.