The segments of a tapeworm consisting primarily of eggs, which hang in bags as a long chain behind the head, are called :

Options

A. proglottids
B. cercaria
C. sporocysts
D. scolexes

Explanation

To answer the question regarding the segments of a tapeworm that consist primarily of eggs and hang in bags as a long chain behind the head, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of a Tapeworm**:
- Tapeworms belong to the class Cestoda. They have a distinct body structure that includes a head (scolex), a neck, and a series of segments called proglottids.

2. **Identify the Segments**:
- The segments of a tapeworm are called proglottids. These segments are formed from the neck region and can be numerous, forming a long chain behind the head.

3. **Function of Proglottids**:
- Each proglottid is involved in sexual reproduction and is hermaphroditic, meaning it contains both male and female reproductive organs. This allows for fertilization to occur either with neighboring proglottids or within the same proglottid.

4. **Egg Production**:
- Proglottids contain a large number of eggs, typically around 50,000 per segment. These eggs are what the question refers to when mentioning segments that consist primarily of eggs.

5. **Elimination of Incorrect Options**:
- The other options provided (sarcaria, sporocyst, and scolex) do not fit the description:
- **Sarcaria**: This is a larval form of trematodes, not related to tapeworm segments.
- **Sporocyst**: Refers to a cyst containing spores or reproductive cells, not specific to tapeworm segments.
- **Scolex**: This is the head of the tapeworm, which is not involved in egg production.

6. **Conclusion**:
- Based on the understanding of tapeworm anatomy and the functions of its segments, the correct answer to the question is **proglottids**.

### Final Answer:
The segments of a tapeworm consisting primarily of eggs, which hang in bags as a long chain behind the head, are called **proglottids**.

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