Which of the following is not a fundamental character of a chordate?

Options

A. Rod like soild structure Notochord present dorsally.
B. Solid , ventral and double nerve cord
C. Paired Pharyngeal gill slits
D. Heart is ventral in all

Answer

To solve the question "Which of the following is not a fundamental character of a chordate?", we will analyze each option based on the fundamental characteristics of chordates.

### Step-by-Step Solution:

1. **Identify Fundamental Characteristics of Chordates**:
- Chordates are characterized by three main features:
- Presence of a notochord (a rod-like solid structure) which is present dorsally.
- A dorsal hollow nerve cord.
- Paired pharyngeal gill slits.

2. **Evaluate Each Option**:
- **Option A: Rod-like solid structure called notochord present dorsally**:
- This is a fundamental characteristic of chordates. Therefore, this option is not the answer.

- **Option B: Solid ventral and double nerve cord**:
- Chordates have a dorsal hollow nerve cord, not a solid ventral double nerve cord. This is a characteristic feature of arthropods. Thus, this option is likely the answer.

- **Option C: Paired pharyngeal gill slits**:
- This is also a fundamental characteristic of chordates. Therefore, this option is not the answer.

- **Option D: Heart as ventral in all**:
- While the heart is ventral in many chordates, it is not a defining characteristic that applies to all chordates. However, it is still considered a common feature. Thus, this option is not the answer.

3. **Conclusion**:
- The only option that does not represent a fundamental characteristic of chordates is **Option B: Solid ventral and double nerve cord**.

### Final Answer:
**Option B: Solid ventral and double nerve cord** is not a fundamental character of a chordate.