Which is a connecting link between fishes and amphibians

Options

A. Catfish
B. Gambusia
C. Protopterus
D. Clupea

Answer

To determine the connecting link between fishes and amphibians, we need to analyze the characteristics of the given options and understand what a connecting link is.

### Step-by-Step Solution:

1. **Understand the Concept of a Connecting Link**:
- A connecting link is an organism that exhibits characteristics of two different groups of organisms, in this case, fishes and amphibians.

2. **Analyze the Options**:
- **Catfish**: This is a type of fish and does not have amphibian characteristics.
- **Gambusia**: This is also a fish, specifically a small freshwater fish, and lacks amphibian traits.
- **Protopterus**: This is known as a lungfish. It possesses both fish-like and amphibian-like characteristics, as it has lungs for breathing air and can survive in both aquatic and terrestrial environments.
- **Clupea**: This is another type of fish, commonly known as herring, and does not show amphibian characteristics.

3. **Identify the Correct Answer**:
- Among the options, **Protopterus** stands out as it has features of both fishes (being aquatic) and amphibians (having lungs for breathing air). Therefore, it serves as the connecting link between the two groups.

4. **Conclusion**:
- The correct answer to the question "Which is a connecting link between fishes and amphibians?" is **Protopterus**.