Alimentary canal is absent in

Options

A. Taenia and schistosoma
B. Ascaris and fasciola
C. Taenia and Echinococcus
D. tricuris and Fasciola

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which organisms lack an alimentary canal. An alimentary canal is a digestive tract that allows for the intake and processing of food.

2. **Identifying the Options**: The options provided are:
- Option 1: Tenia and Schistosoma
- Option 2: Ascaris and Fasciola
- Option 3: Tenia and Echinococcus
- Option 4: Trichuris and Fasciola

3. **Analyzing Each Option**:
- **Option 1 (Tenia and Schistosoma)**: Tenia (tapeworm) is known to lack an alimentary canal, while Schistosoma (a type of fluke) has a digestive system.
- **Option 2 (Ascaris and Fasciola)**: Ascaris (a roundworm) has a complete digestive system, and Fasciola (a liver fluke) also has an alimentary canal.
- **Option 3 (Tenia and Echinococcus)**: Both Tenia (tapeworm) and Echinococcus (dog tapeworm) are endoparasites and lack an alimentary canal.
- **Option 4 (Trichuris and Fasciola)**: Trichuris (whipworm) has a digestive system, and Fasciola has an alimentary canal.

4. **Conclusion**: From the analysis, the correct answer is Option 3: Tenia and Echinococcus, as both of these organisms are endoparasites that do not possess an alimentary canal.

**Final Answer**: The alimentary canal is absent in Tenia and Echinococcus (Option 3).

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