The presence of tube feet is the characteristic feature of phylum

Options

A. Annelida
B. Mollusca
C. Arthropoda
D. Echinodermata

Answer

### Step-by-Step Solution:

1. **Identify the Key Feature**: The question asks about the characteristic feature of a phylum associated with tube feet.

2. **Define Tube Feet**: Tube feet are small, tubular projections that are part of the water vascular system in certain marine animals. They are primarily located on the oral surface.

3. **Relate Tube Feet to Echinoderms**: Tube feet are a distinctive feature of echinoderms, which include organisms like sea urchins and sea cucumbers. They serve various functions such as locomotion, respiration, and feeding.

4. **Evaluate Other Phyla**:
- **Annelida**: This phylum is characterized by segmented worms that use parapodia for locomotion, not tube feet.
- **Mollusca**: Mollusks have a muscular foot for movement, which is different from tube feet.
- **Arthropoda**: Arthropods have jointed appendages for locomotion, which do not include tube feet.

5. **Conclude the Correct Phylum**: Since tube feet are exclusively found in echinoderms, the correct answer to the question is the phylum Echinodermata.

### Final Answer:
The presence of tube feet is a characteristic feature of the phylum **Echinodermata**.