Torsion and detorsion are characteristic features in

Options

A. Mollusca
B. Arthropoda
C. Annelida
D. Protozoa

Answer

**Step-by-Step Solution:**

1. **Understanding Torsion and Detorsion**: Torsion refers to the twisting of the visceral mass in certain organisms, which leads to a change in body symmetry. Detorsion is the process of uncoiling or untwisting that occurs after torsion.

2. **Identifying the Organisms**: Torsion and detorsion are characteristic features of organisms in the phylum Mollusca, specifically within the class Gastropoda.

3. **Characteristics of Gastropoda**: Members of the class Gastropoda exhibit a unique body plan where the visceral hump undergoes torsion. This results in a shift of the internal organs, which can affect their bilateral symmetry.

4. **Function of Torsion**: The torsion process allows gastropods to position their body in a way that facilitates feeding and digestion. It helps in the reabsorption of nutrients as well.

5. **Conclusion**: Therefore, torsion and detorsion are characteristic features of the members of the class Gastropoda within the phylum Mollusca.

**Final Answer**: Torsion and detorsion are characteristic features in the class Gastropoda of the phylum Mollusca.

---