Find the organism in which blood vascular system, respiratory system and even alimentary canal are absent.

Options

A.
B.
C.
D.

Answer

To find the organism that lacks a blood vascular system, respiratory system, and alimentary canal, we can analyze the options provided in the question.

### Step-by-Step Solution:

1. **Understand the Requirements**: We need to identify an organism that does not possess a blood vascular system, respiratory system, or alimentary canal.

2. **Analyze the Organisms**:
- **Fasciola hepatica (Liver Fluke)**: This is a flatworm belonging to the phylum Platyhelminthes. While it has a simplified digestive system, it does not have a true blood vascular system or respiratory system, but it does have a gastrovascular cavity for digestion.
- **Butterfly**: This organism belongs to the phylum Arthropoda. It has a complex circulatory system (open circulatory system) and a respiratory system (tracheal system), along with a complete alimentary canal.
- **Octopus**: This marine organism belongs to the phylum Mollusca. It has a closed circulatory system, a respiratory system (gills), and a complete alimentary canal.
- **Tapeworm**: Another member of the phylum Platyhelminthes, tapeworms also lack a true digestive system and have a simplified structure. They absorb nutrients directly through their skin.

3. **Identify the Correct Organism**: Among the options analyzed, both liver fluke and tapeworm are members of the phylum Platyhelminthes and lack a true blood vascular system and respiratory system. However, they do have a form of digestive structure (gastrovascular cavity for liver fluke and absorption for tapeworm).

4. **Conclusion**: The organism that fits the criteria of lacking a blood vascular system, respiratory system, and alimentary canal is the **tapeworm** (specifically, it can be considered as it absorbs nutrients directly without a digestive tract).

### Final Answer: Tapeworm (a member of phylum Platyhelminthes).