All vertebrates except Myxine are

Options

A. unisexual
B. bisexual
C. both (1) & (2)
D. none of these

Answer

To solve the question "All vertebrates except Myxine are:", we will analyze the information provided about vertebrates and Myxine.

### Step-by-Step Solution:

1. **Understanding Myxine**:
- Myxine is a type of vertebrate that belongs to the family Myxinoidae. It is classified as a jawless fish (agnathan).

2. **Classification of Vertebrates**:
- Vertebrates are divided into two major groups:
- **Gnathostomes**: Jawed vertebrates (includes bony and cartilaginous fish, amphibians, reptiles, birds, and mammals).
- **Agnathans**: Jawless vertebrates (includes Myxine and other similar organisms).

3. **Reproductive Strategies**:
- **Unisexual**: Organisms that produce male and female gametes in separate individuals. Most vertebrates fall into this category.
- **Bisexual (or Hermaphrodite)**: Organisms that can produce both male and female gametes within the same individual. Myxine is an example of this.

4. **Conclusion**:
- Since Myxine is hermaphroditic, it is the exception among vertebrates. All other vertebrates (except Myxine) are unisexual.

5. **Final Answer**:
- Therefore, the correct answer to the question "All vertebrates except Myxine are" is **unisexual**.