Absence of jaw is the feature of
(a) Myxine
(b) Eptatretus
(c) Petromyzon
(d) All of these

Options

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

Answer

To solve the question regarding the absence of jaws in certain organisms, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which of the given options lacks jaws. The options provided are Myxine, Eptatretus, Petromyzon, and "All of these".

2. **Identify the Organisms**:
- **Myxine**: Commonly known as hagfish, this organism is known for its jawless structure.
- **Eptatretus**: This is another type of hagfish, also jawless.
- **Petromyzon**: Known as the sea lamprey, this organism is also classified as jawless.

3. **Define Jawless Organisms**: Organisms that lack jaws are classified under a group known as Agnatha. This term literally means "jawless" and includes species like hagfish and lampreys.

4. **Analyze the Options**:
- Since all three organisms listed (Myxine, Eptatretus, and Petromyzon) are jawless, we can conclude that they all fit the criteria mentioned in the question.

5. **Select the Correct Answer**: Since all the listed organisms do not have jaws, the correct answer is (d) All of these.

### Final Answer:
The absence of jaw is a feature of (d) All of these.

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