Which of the following represents the correct combination without any exception
`{:(,"Characteristics","Class",),((a),"Mouth ventrcal, gills without operculum, skin with placoid scales, persistent notochord","Chondrichthyes",),((b),"Sucking and circular mouth, jaws absent, integument without scales, paired appendages","Cyclostomata",),((c),"Body covered with feather, skin mosit and glandular, fore-limbs form wings, lungs from wings, lungs with air sacs","Aves",),((d),"Mammary gland, hair on body, pinnae, two pair of limbs","Mammalia",):}`

Options

A. Characteristics- Body covered with feathers, skin moist and glandular, fore-limbs form wings, lungs with air sacs, Class-Aves
B. Characteristics-Mammary gland, hair on body, pinnae, two pairs of limbs, Class-Mammalia
C. Characteristics-mouth ventral, gills wihout operculum, skin with placoid scales, persistent notochord, class-chondrichthyes
D. Characteristics-Sucking and circular mouth, jaws absent, integument wihout scales, paired appendges, Class- Cyclostomata

Answer

To solve the question regarding the correct combination of characteristics and their corresponding classes in the animal kingdom, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Analyze Option (a) - Chondrichthyes**:
- Characteristics:
- Mouth ventral
- Gills without operculum
- Skin with placoid scales
- Persistent notochord
- Analysis:
- All characteristics match perfectly with Chondrichthyes.
- **Conclusion**: This option is correct.

2. **Analyze Option (b) - Cyclostomata**:
- Characteristics:
- Sucking and circular mouth
- Jaws absent
- Integument without scales
- Paired appendages
- Analysis:
- The first three characteristics match, but Cyclostomata lacks paired appendages (it has median fins instead).
- **Conclusion**: This option is incorrect due to the mismatch in paired appendages.

3. **Analyze Option (c) - Aves**:
- Characteristics:
- Body covered with feathers
- Skin moist and glandular
- Fore-limbs form wings
- Lungs with air sacs
- Analysis:
- The body is covered with feathers and fore-limbs form wings are correct, but the skin is not moist and glandular; it is thin, dry, and non-glandular.
- **Conclusion**: This option is incorrect due to the mismatch regarding skin characteristics.

4. **Analyze Option (d) - Mammalia**:
- Characteristics:
- Mammary gland
- Hair on body
- Pinnae
- Two pairs of limbs
- Analysis:
- Mammary glands, hair on body, and two pairs of limbs are correct. However, pinnae are not present in all mammals (e.g., monotremes).
- **Conclusion**: This option is incorrect due to the exception regarding pinnae.

### Final Conclusion:
The only option that matches all characteristics without any exceptions is **Option (a) - Chondrichthyes**.