Which is not a characteristic of chordates

Options

A. Pharyngeal gill slits
B. Dorsal nerve cord
C. Notochord
D. Diploblastic

Answer

To determine which option is not a characteristic of chordates, we can analyze the given options based on the known characteristics of this phylum.

### Step-by-Step Solution:

1. **Understanding Chordates**: Chordates are a diverse group of animals that share certain key characteristics at some stage of their development. These characteristics include:
- Notochord
- Dorsal hollow nerve cord
- Pharyngeal gill slits
- Post-anal tail
- Endostyle or thyroid gland

2. **Analyzing the Options**:
- **Notochord**: This is a defining feature of chordates. It is a flexible rod-like structure that provides support.
- **Dorsal Hollow Nerve Cord**: This is another key characteristic of chordates. It runs along the back and is a precursor to the spinal cord in vertebrates.
- **Pharyngeal Gill Slits**: These structures are present in the embryonic stage of all chordates and are used for filter feeding or respiration in aquatic species.
- **Diploblastic**: This term refers to organisms that have two germ layers (ectoderm and endoderm). Chordates, however, are triploblastic, meaning they have three germ layers (ectoderm, mesoderm, and endoderm).

3. **Identifying the Incorrect Characteristic**: Among the options provided, "diploblastic" is the only term that does not apply to chordates, as they are triploblastic.

4. **Conclusion**: Therefore, the characteristic that is not associated with chordates is **diploblastic**.

### Final Answer:
The characteristic that is not a characteristic of chordates is **diploblastic**.

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