The correct option for the question regarding the parts used by the tapeworm to fasten itself to the host’s intestine is B. Hooks and suckers. Detailed Explanation:

1. Understanding Tapeworm Anatomy:
2. Tapeworms, which belong to the class Cestoda, are parasitic flatworms that live in the intestines of their hosts. They have a unique structure that allows them to attach firmly to the intestinal wall of their host.
3. Key Structures for Attachment:
4. The primary structures that tapeworms use to attach to the host's intestine are hooks and suckers.
5. Suckers are disc-like structures located on the scolex (the head of the tapeworm) that create a vacuum to hold onto the intestinal wall.
6. Hooks are small, sharp structures that can also be found on the scolex, which help to anchor the tapeworm more securely to the host's intestinal lining.
7. Why Option B is Correct:
8. Option B correctly identifies both hooks and suckers as the parts used for attachment. The combination of these two structures provides a strong grip, allowing the tapeworm to remain in place despite the movement of the host's intestines and the flow of digested food.

Why Other Options are Incorrect:

• Option A: Neck and suckers:
• The neck of the tapeworm is not involved in attachment. It is the region that connects the scolex to the proglottids (segments of the tapeworm). While suckers are indeed used for attachment, the neck does not play a role in this function.
• Option C: Rostellum and suckers:
• The rostellum is a structure that may bear hooks in some species of tapeworms, but it is not universally present in all tapeworms. Moreover, the term "rostellum" is more specific and not as commonly used as "hooks" in the context of attachment. Therefore, while it may be relevant for some species, it does not encompass the general mechanism of attachment for all tapeworms.
• Option D: Young proglottis and neck:
• Young proglottids are segments of the tapeworm that develop after the scolex and are not involved in attachment. The neck, as mentioned earlier, connects the scolex to the proglottids and does not serve any attachment function. Thus, this option is incorrect.

Summary of Key Points:

• Tapeworms use hooks and suckers to attach to the host's intestine.
• The scolex is the part of the tapeworm that contains these structures.
• The neck and proglottids do not play a role in attachment.
• Understanding the anatomy of tapeworms is crucial for recognizing how they interact with their hosts.

This detailed breakdown should help reinforce your understanding of tapeworm anatomy and their methods of attachment, which is essential for any biology exam focused on parasitology or animal physiology.