Question

Which of the following animals can regenerate arms and parts of the body?
1. Starfish
2. Brittle star
3. Sea lily
4. Aves
(a)1, 2, and 3
(b)1 and 2
(c)2 and 4
(d)1 and 3

Answer 1

Regeneration is a trait that allows many organisms belonging to some families to regenerate or regrow limbs or other body parts that are lost in injury. This characteristic is found majorly in species that are found in water.

Complete step by step answer:
The aquatic animal’s starfish, brittle star, and sea lily are animals that can regenerate arms and parts of their body. These animals belong to the Echinodermata phylum.
- Echinoderms can regenerate their appendages or limbs, internal organs, and some parts of the nervous system.
- Some species of starfish can regrow their body even half of their body is missing. However, if the radial nerve is severed when the limb of the starfish is amputated, regeneration does not occur.
- Some brittle stars and sea stars are known to reproduce asexually by splitting themselves in half.

So, the correct answer is ‘1, 2, and 3’.

Additional information: Regeneration of body parts is also observed in arthropods, annelids, Platyhelminthes, amphibians, and hydra.
- Aves do not have regenerative abilities but can grow their feathers back and can heal their wounds.
- Sea lilies belong to the class Crinoidea which contains the animal’s sea lilies and feather stars.
- When a limb of a starfish is damaged, they can self-amputate it to restart regeneration.

Note:
In some cases, an entirely new organism can grow from a severed appendage in starfish.
- Other examples of regeneration in animals include planarians or flatworms that when cut into pieces, each piece can grow into a new worm, and spiders that can regrow missing legs or parts of legs.