Jawless vertebrates belong to the group

Options

A. Agnatha
B. Gnathostomata
C. Lagomorpha
D. Prototheria

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the group to which jawless vertebrates belong.

2. **Analyzing the Options**:
- **Option 1: Gnatha**: This term refers to jawless vertebrates. It includes groups like armoured fishes and cyclostomes, which are characterized by their circular mouths.
- **Option 2: Gnathostomata**: This group includes jawed vertebrates, which is the opposite of what we are looking for.
- **Option 3: Lagomorpha**: This is a taxonomic order that includes animals like rabbits, which are jawed vertebrates.
- **Option 4: Prototheria**: This is a former subclass of mammals that also have jaws, and the term is not commonly used anymore.

3. **Identifying the Correct Answer**: Based on the definitions and characteristics of each option, it is clear that the group that includes jawless vertebrates is **Gnatha**.

4. **Conclusion**: Therefore, the correct answer to the question is **Gnatha**.