Which one of the following groups of animals is correcty matched with its characters without even a single exception in the group ?

Options

A. Reptilia : Dry cornified skin , three chambered heart
B. Osteichthyes : Four pairs of gills , an operaculum covers gill - slits on each sides
C. Amphibia : Skin without scales , two pairs of limbs
D. Mammalia : Diaphragm for breathing , ear

Answer

To solve the question, we need to analyze each group of animals and their corresponding characteristics to determine which group is correctly matched without any exceptions.

### Step-by-Step Solution:

1. **Analyze the first option: Reptilia**
- Characteristics: Dry, cornified skin; three-chambered heart.
- Exception: Crocodiles, which are reptiles, have a four-chambered heart.
- Conclusion: This option is not correctly matched.

2. **Analyze the second option: Osteichthyes (Bony fishes)**
- Characteristics: Four pairs of gills and operculum covering the gills.
- Exception: Lungfishes, which are also classified as bony fishes, have lungs for respiration and do not possess gills.
- Conclusion: This option is not correctly matched.

3. **Analyze the third option: Amphibia**
- Characteristics: Skin without scales; two pairs of limbs.
- Exception: Caecilians, which belong to the class Amphibia, are limbless and have a different body structure.
- Conclusion: This option is not correctly matched.

4. **Analyze the fourth option: Mammalia (Mammals)**
- Characteristics: Presence of mammary glands; diaphragm for breathing; ears.
- Exception: There are no known exceptions to these characteristics within the class Mammalia.
- Conclusion: This option is correctly matched without any exceptions.

### Final Answer:
The group of animals that is correctly matched with its characters without any exceptions is **Mammalia**.

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