In which of the following pairs , is the ear represented by tympanum ?

Options

A. Fishes and amphibians
B. Amphibians and reptiles
C. Reptiles and birds
D. Amphibians and mammals

Answer

To solve the question "In which of the following pairs is the ear represented by tympanum?", we need to understand what the tympanum is and in which organisms it is found.

### Step-by-Step Solution:

1. **Definition of Tympanum**:
- The tympanum is an external ear structure, commonly referred to as the eardrum. It plays a crucial role in hearing by transmitting sound waves to the middle ear.

2. **Function of Tympanum**:
- The tympanum vibrates in response to sound waves, which then pass these vibrations to the ossicles in the middle ear, and subsequently to the inner ear.

3. **Presence in Organisms**:
- The tympanum is notably present in certain groups of animals. Specifically, it is found in:
- **Amphibians**: For example, frogs have a tympanum that serves as their external ear.
- **Reptiles**: Many reptiles also possess a tympanum.
- It is important to note that the tympanum is not present in fishes or birds.

4. **Evaluating the Options**:
- We need to check the given pairs in the question to identify which ones include organisms that have a tympanum.
- Based on our understanding:
- **Amphibians** (e.g., frogs) and **Reptiles** (e.g., lizards) both have tympanum.
- **Fishes** do not have a tympanum.
- **Birds** do not have a tympanum.

5. **Conclusion**:
- The correct answer to the question is the pair that includes both amphibians and reptiles, as they are the groups where the tympanum is represented as the ear.

### Final Answer:
- The correct option is **Option 2**, which includes amphibians and reptiles.