Which one of the following stages does not occur in the life -history of liver fluke ?

Options

A. Cercaria
B. Cysticercus
C. Miracidium
D. Redia

Answer

To determine which stage does not occur in the life history of the liver fluke (Fasciola), we can analyze the options provided and understand the life cycle of the liver fluke.

### Step-by-Step Solution:

1. **Understand the Life Cycle of Liver Fluke (Fasciola)**:
- The liver fluke undergoes several developmental stages in its life cycle, including eggs, miracidium, sporocyst, redia, and cercaria.
- The adult liver fluke resides in the liver of its definitive host, usually a mammal.

2. **Analyze the Options**:
- **Option 1: Sarcaria**: This is a free-swimming larval stage found in some parasites, but it is not associated with liver flukes.
- **Option 2: Cysticercus**: This larval form is associated with Taenia (tapeworms) and is not part of the liver fluke's life cycle.
- **Option 3: Miracidium**: This is a free-swimming larval stage that hatches from the egg and is indeed part of the liver fluke's life cycle.
- **Option 4: Redia**: This stage is also present in the life cycle of the liver fluke, developing within the snail host.

3. **Identify the Incorrect Stage**:
- From the analysis, we see that the **cysticercus** stage does not occur in the life history of the liver fluke. It is specifically associated with Taenia species.

4. **Conclusion**:
- The stage that does not occur in the life history of the liver fluke is **Cysticercus**.

### Final Answer:
Cysticercus does not occur in the life history of the liver fluke (Fasciola).

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