As compared to cartilaginous fishes, bony fishes have dorsal fin

Options

A. Single instead of two
B. Two instead of one
C. Single in both
D. Two in both

Answer

To answer the question regarding the number of dorsal fins in cartilaginous fishes compared to bony fishes, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Fishes**:
- Understand that there are two main categories of fishes: cartilaginous fishes (like sharks and rays) and bony fishes (like salmon and goldfish).

2. **Examine Dorsal Fins in Cartilaginous Fishes**:
- Cartilaginous fishes typically have **two dorsal fins**. These fins are located on the top of their bodies and are used for stabilization and maneuvering.

3. **Examine Dorsal Fins in Bony Fishes**:
- Bony fishes, on the other hand, usually have **one dorsal fin**. This fin also serves a similar purpose in terms of stabilization and movement.

4. **Compare the Findings**:
- Now, we compare the dorsal fins of both types of fishes:
- Cartilaginous fishes: **Two dorsal fins**
- Bony fishes: **One dorsal fin**

5. **Choose the Correct Option**:
- Based on the comparison, the correct answer to the question "As compared to cartilaginous fishes, bony fishes have dorsal fin" is that bony fishes have **one dorsal fin** instead of two.

### Conclusion:
The correct answer is **option 1: single instead of two**.