Which one of the following pairs of animals comprises "Jawless fishes"
(a) Guppies and hag fishes
(b) Lampreys and eels
(c) Mackerels and Rohu
(d) Lampreys and hag fishes

Options

A. Guppies and hag fishes
B. Lampreys and eels
C. Mackerels and Rohu
D. Lampreys and hag fishes

Answer

To determine which pair of animals comprises "Jawless fishes," we need to identify the characteristics of jawless fishes and the examples provided in the options.

### Step-by-Step Solution:

1. **Understand Jawless Fishes**: Jawless fishes belong to the class Cyclostomata. They are characterized by the absence of jaws and have a circular mouth. The two most common examples of jawless fishes are hagfishes and lampreys.

2. **Analyze the Options**:
- **Option (a)**: Guppies and hag fishes
- Guppies are not jawless fishes; they have jaws. Therefore, this option is incorrect.
- **Option (b)**: Lampreys and eels
- Eels are jawed fishes. Thus, this option is also incorrect.
- **Option (c)**: Mackerels and Rohu
- Both mackerels and Rohu are jawed fishes. Hence, this option is incorrect.
- **Option (d)**: Lampreys and hag fishes
- Both lampreys and hag fishes are jawless fishes. Therefore, this option is correct.

3. **Conclusion**: The correct pair of animals that comprises "Jawless fishes" is **Option (d)**: Lampreys and hag fishes.

### Final Answer:
**Option (d)**: Lampreys and hag fishes.

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