Tube feet are without suckers in

Options

A. Echinoidea
B. Ophiuroidea
C. Crinoidea
D. Both B and C.

Answer

To solve the question "Tube feet are without suckers in," we will analyze the options provided and determine which echinoderm classes have tube feet that lack suckers.

### Step-by-Step Solution:

1. **Understanding Tube Feet**:
- Tube feet are small, flexible, and elongated structures found in echinoderms, primarily used for locomotion, feeding, and respiration.
- They can be found on the oral side or the underside of echinoderms.

2. **Forms of Tube Feet**:
- Tube feet can be categorized into two forms:
- With suckers
- Without suckers

3. **Analyzing the Options**:
- **Option A: Echinoidea**: This class includes sea urchins and sand dollars, which typically have tube feet with suckers.
- **Option B: Ophiuroidea**: This class includes brittle stars and basket stars, which have tube feet without suckers.
- **Option C: Crinoidea**: This class includes sea lilies and feather stars, which also have tube feet without suckers.
- **Option D: B and C both**: This option suggests that both Ophiuroidea and Crinoidea have tube feet without suckers.

4. **Conclusion**:
- Since both Ophiuroidea and Crinoidea have tube feet without suckers, the correct answer is **Option D: B and C both**.

### Final Answer:
The correct option is **D: B and C both (Ophiuroidea and Crinoidea)**.

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