Which one of the following is not a characteristic feature of subphylum Vertebrata?

Options

A. Doral tubular nerve cord
B. Ventral mascular heart
C. Presence of notochord in adult
D. Presence of kidneys

Answer

To determine which of the following is not a characteristic feature of the subphylum Vertebrata, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand the Characteristics of Vertebrata**:
- The subphylum Vertebrata is known for specific features, including a dorsal tubular nerve cord, a ventral muscular heart, kidneys, and a notochord (which typically develops into the vertebral column in adults).

2. **Evaluate Option 1: Dorsal Tubular Nerve Cord**:
- This is a characteristic feature of Vertebrata. It forms the central nervous system and is present in all vertebrates. Therefore, this option does not answer the question.

3. **Evaluate Option 2: Ventral Muscular Heart**:
- Vertebrates possess a ventral muscular heart, which is essential for circulation. This is also a characteristic feature of the subphylum. Hence, this option is not the answer.

4. **Evaluate Option 3: Presence of Notochord in Adult**:
- In adult vertebrates, the notochord typically develops into the vertebral column (spine). Therefore, the presence of a notochord in adults is not a characteristic feature of Vertebrata. This option is likely the correct answer to the question.

5. **Evaluate Option 4: Presence of Kidneys**:
- Kidneys are present in vertebrates and play a crucial role in excretion and osmoregulation. Thus, this option is also a characteristic feature of Vertebrata.

### Conclusion:
Based on the evaluation, the correct answer is **Option 3: Presence of notochord in adult**. This is not a characteristic feature of subphylum Vertebrata, as the notochord is replaced by the vertebral column in adults.