According to habitats, all echinoderms are____animals.

Options

A. Fresh water
B. Marine
C. Terrestrial
D. Fresh water and marine

Explanation

To answer the question "According to habitats, all echinoderms are____animals," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Echinoderms**:
- Echinoderms belong to the phylum Echinodermata. This phylum includes various marine animals such as starfish, sea urchins, and sea cucumbers.

2. **Identifying the Habitat**:
- Echinoderms are primarily found in marine environments. They inhabit oceans and seas, which means they are exclusively marine animals.

3. **Evaluating the Options**:
- The options provided are:
- Freshwater
- Marine
- Terrestrial
- Freshwater and Marine
- We need to determine which of these options correctly describes the habitat of echinoderms.

4. **Analyzing Each Option**:
- **Freshwater**: Incorrect, as echinoderms do not live in freshwater environments.
- **Marine**: Correct, as all echinoderms are found in marine habitats.
- **Terrestrial**: Incorrect, since echinoderms are not land-dwelling animals.
- **Freshwater and Marine**: Incorrect, as echinoderms are exclusively marine.

5. **Conclusion**:
- Based on the analysis, the correct answer to the question is "marine."

### Final Answer:
According to habitats, all echinoderms are **marine** animals.

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