Ascaris is specialised and not degenerated parasite as it is

Options

A. With a straight alimentary canal
B. Dioecious
C. Without respiratoty organ
D. Covered by cuticle resistant to digestive juices of host

Answer

### Step-by-Step Solution:

1. **Understanding Ascaris**: Ascaris is a genus of parasitic worms, commonly known as roundworms. They are known for their adaptations that enable them to thrive in a host organism.

2. **Morphological Adaptations**:
- The mouth of Ascaris is equipped with three lips.
- These lips help the parasite attach to the mucus membrane of the host's intestine, which is crucial for its survival as a parasite.

3. **Anatomical Adaptations**:
- Ascaris has a muscular pharynx that aids in the ingestion of food through a sucking action.
- Notably, Ascaris lacks digestive glands, which is an adaptation to its parasitic lifestyle since it absorbs nutrients directly from the host.

4. **Physiological Adaptations**:
- The body wall of Ascaris is covered with a tough, thick cuticle.
- This cuticle serves as a protective barrier against the digestive enzymes and antitoxins produced by the host, allowing Ascaris to survive and thrive within the host's digestive system.

5. **Other Characteristics**:
- Ascaris has a straight elementary canal, which is efficient for its parasitic mode of life.
- It is dioecious, meaning that male and female reproductive organs are found in separate individuals.
- Ascaris does not possess a respiratory system, which is another adaptation to its parasitic lifestyle.

6. **Conclusion**:
- The key feature that makes Ascaris a specialized parasite is its cuticle, which is resistant to the digestive juices of the host. This adaptation is crucial for its survival and effectiveness as a parasite.

### Final Answer:
Ascaris is specialized and not a degenerated parasite primarily because it is covered by a cuticle that is resistant to the digestive juices of the host.

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