Absence of jaw is the feature of

Options

A. Myxine
B. Eptatretus
C. Petromyzon
D. All of these

Answer

To solve the question "Absence of jaw is the feature of," we will analyze the options provided and relate them to the characteristics of different classes of organisms.

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking which group of organisms is characterized by the absence of jaws.

2. **Identifying the Options**: The options given are:
- A) Mixing
- B) Aptatitis
- C) Petromycin
- D) All of these

3. **Researching the Characteristics**:
- The absence of jaws is a notable feature of a specific class of fish known as Cyclostomata.
- Cyclostomes include organisms like lampreys and hagfish, which are characterized by their jawless bodies.

4. **Analyzing the Options**:
- **Mixing**: This does not correspond to any known biological classification.
- **Aptatitis**: This term does not relate to any known class in zoology.
- **Petromycin**: This also does not correspond to a known classification.
- **All of these**: Since the first three options do not represent valid biological classes, this option suggests that they all share the characteristic of being jawless, which is incorrect.

5. **Conclusion**: Since none of the options A, B, or C are valid classifications that represent organisms with the absence of jaws, the best answer based on the context provided in the video is that the absence of jaws is a feature of Cyclostomata, which is not directly listed in the options. However, if we must choose from the given options, we can conclude that the answer is **D) All of these**, as it implies that they all share the characteristic of being jawless.

### Final Answer: D) All of these