Which constitutes the correct pairing

Options

A. Flatworms -planaria
B. Dogfish -Sea Urchin
C. Fish - Snail
D. None of the above

Answer

To solve the question "Which constitutes the correct pairing?" we will analyze each option provided:

1. **Option 1: Flatworms - Planaria**
- Planaria is a type of flatworm that belongs to the phylum Platyhelminthes. It is characterized by its dorsoventrally flattened body. Therefore, this pairing is correct.

2. **Option 2: Dogfish - Sea Urchin**
- The dogfish is a type of shark, which belongs to the class Chondrichthyes (fishes). On the other hand, the sea urchin belongs to the phylum Echinodermata. Since these two organisms belong to different phyla, this pairing is incorrect.

3. **Option 3: Fish - Snail**
- Fish belong to the phylum Chordata, while snails belong to the phylum Mollusca. Since these two organisms also belong to different phyla, this pairing is incorrect.

4. **Option 4: None of the above**
- Since we have established that the first option (Flatworms - Planaria) is correct, this option is also incorrect.

Based on the analysis above, the correct answer is **Option 1: Flatworms - Planaria**.