Sharks and bony fish are different in that only :

Options

A. bony fish have paired fins
B. bony fish have an operculum
C. sharks have a bony skeleton
D. sharks are predaceous

Explanation

To solve the question "Sharks and bony fish are different in that only:", we will analyze each option provided and determine which one correctly highlights the difference between sharks and bony fish.

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify the key difference between sharks (which are cartilaginous fish) and bony fish (which have a bony skeleton).

2. **Evaluate Each Option**:
- **Option 1: Bony fish have paired fins**.
- While it is true that bony fish have paired fins, sharks also have paired fins. This option does not differentiate them.

- **Option 2: Bony fish have an operculum**.
- This is a significant difference. Bony fish possess an operculum, which is a bony flap covering their gills. Sharks do not have this structure. This option could be the correct answer.

- **Option 3: Sharks have a bony skeleton**.
- This statement is incorrect. Sharks have a cartilaginous skeleton, not a bony one. Therefore, this option can be eliminated.

- **Option 4: Sharks are predacious**.
- While sharks are indeed predatory, this characteristic is not exclusive to them, as many bony fish are also predatory. Thus, this option does not serve as a distinguishing feature.

3. **Conclusion**: After evaluating all options, the only correct answer that highlights a difference between sharks and bony fish is **Option 2: Bony fish have an operculum**. This structure is unique to bony fish and is not present in sharks.

### Final Answer:
The correct answer is **Option 2: Bony fish have an operculum**.

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