Which of the following is an unsegmented and viviparous worm?

Options

A. Ascaris
B. Filaria
C. Taenia
D. Fasciola

Answer

To solve the question "Which of the following is an unsegmented and viviparous worm?" we will analyze each option provided: Ascaris, Filaria, Taenia, and Fischiolia.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Unsegmented**: This means that the organism's body is not divided into segments. For example, segmented worms like earthworms have distinct body segments, while unsegmented worms have a smooth, continuous body.
- **Viviparous**: This refers to organisms that give birth to live young rather than laying eggs. In viviparous organisms, the young develop inside the body of the parent.

2. **Analyzing the Options**:
- **Ascaris**: Ascaris is a type of roundworm (nematode) that is segmented in its developmental stages. It is not viviparous; it lays eggs.
- **Filaria**: Filaria is also a nematode, and it is known to be unsegmented. It is viviparous, as it gives birth to live young that develop inside the female's body.
- **Taenia**: Taenia is a type of flatworm (cestode) and is segmented. It is not viviparous; it lays eggs.
- **Fischiolia**: This is not a commonly recognized term in biology. It may refer to a specific organism, but it is not widely known, and its classification as segmented or viviparous is unclear.

3. **Conclusion**:
- Based on the analysis, the only organism that is both unsegmented and viviparous is **Filaria**. It is known to cause the disease filariasis and is transmitted through mosquito bites.

### Final Answer:
The correct answer is **Filaria**.

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