Of the following types of animals, all are segmented except:

Options

A. arthropods
B. annelids
C. echinoderms
D. chordates

Explanation

To determine which of the following types of animals are segmented except for one, we will analyze each option: arthropods, annelids, echinoderms, and chordates.

### Step-by-Step Solution:

1. **Understanding Segmentation**: Segmentation refers to the division of an animal's body into repetitive segments, both externally and internally. This can involve the repetition of organs and structures.

2. **Analyzing Annelids**:
- Annelids, such as earthworms, are known for their segmented bodies.
- Their bodies are divided into multiple segments, which are visible as rings on the exterior.
- Each segment can contain repeated organs, confirming that annelids are segmented.

3. **Analyzing Arthropods**:
- Arthropods, including insects like honeybees and arachnids like scorpions, also exhibit segmentation.
- They have jointed appendages attached to their segments and can have multiple legs, indicating that they are segmented as well.

4. **Analyzing Echinoderms**:
- Echinoderms, such as starfish, do not exhibit true segmentation.
- They have radial symmetry and lack the segmented body structure seen in annelids and arthropods.
- Although they have some repetitive structures, they are not considered segmented animals.

5. **Analyzing Chordates**:
- Chordates, which include humans, have a different form of segmentation known as heteromeric segmentation.
- While their segmentation is not as obvious externally, they do possess segments that are part of their body structure.

6. **Conclusion**:
- Based on the analysis, annelids and arthropods are segmented, chordates have a form of segmentation, but echinoderms do not exhibit segmentation.
- Therefore, the correct answer to the question is **Echinoderms**.

### Final Answer:
**Echinoderms** are the type of animals that are not segmented.