Single gill-slit on each side covered with operculum is present in

Options

A. All elasmobranchs
B. Some elasmobranchs
C. All teleosts
D. Some teleosts

Answer

To answer the question about which type of fish has a single gill slit on each side covered with an operculum, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Fish**:
- There are two main types of fish: bony fish (Osteichthyes) and cartilaginous fish (Chondrichthyes).

2. **Identify the Characteristics of Bony Fish**:
- Bony fish have a structure called an operculum, which covers their gills. This operculum helps in protecting the gills and aids in respiration.

3. **Identify the Characteristics of Cartilaginous Fish**:
- Cartilaginous fish, such as sharks and rays, do not have an operculum. Their gills are exposed, which allows for respiration while they are swimming.

4. **Focus on the Question**:
- The question specifically asks for a fish that has a single gill slit on each side covered with an operculum. This characteristic is typical of bony fish.

5. **Examples of Bony Fish**:
- Bony fish are also referred to as teleosts. Examples include fish like Rohu and Cutla.

6. **Conclusion**:
- Therefore, the correct answer to the question is that a single gill slit on each side covered with operculum is present in **all teleost fish**.

### Final Answer:
A single gill slit on each side covered with operculum is present in **all teleost fish**.

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