Group where adults are degnerated while larvae are well developed is

Options

A. Tunicata
B. Agnatha
C. Amphibia
D. Cephalochordata

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a group of organisms where the adults are degenerated while the larvae are well developed. This indicates a specific type of metamorphosis.

2. **Identifying the Type of Metamorphosis**: The type of metamorphosis described is known as "retrogressive metamorphosis." In this process, the larval stage is more developed than the adult stage, meaning that as the organism matures, it loses some of its well-developed structures.

3. **Recognizing the Group**: The group that exhibits retrogressive metamorphosis is the Urochordata. Urochordates are also commonly known as tunicates.

4. **Characteristics of Urochordata**: Urochordates have a notochord present in their tail during the larval stage. As they mature into adults, they undergo significant degeneration, leading to a simpler body structure. The adult form is often embedded in a protective tunic or test.

5. **Evaluating the Options**:
- **Option 1: Tunicates** - This is correct as they exhibit retrogressive metamorphosis.
- **Option 2: Agnatha** - These are jawless vertebrates and do not show this type of metamorphosis.
- **Option 3: Amphibia** - This class includes frogs and undergoes progressive metamorphosis.
- **Option 4: Cephalochordata** - These organisms also do not exhibit retrogressive metamorphosis.

6. **Conclusion**: The correct answer to the question is **Option 1: Tunicates**.

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