Study the statements about chordates and identify correct ones
(a) Columella auris present in middle ear of amphians is modified hyomandibula of fishes
(b) Reptiles lay cleidoic eggs
(c) Sphenodon is connecting link between amphibians and reptiles
(d) Panthera tigris is an extinct animal of India .

Options

A. (a) ,(b) , (c)
B. (b) ,(c), (d)
C. (a) , (c), (d)
D. (a) , (b) , (d)

Answer

To solve the question regarding the statements about chordates, we will analyze each statement one by one to determine which ones are correct.

### Step-by-Step Solution:

1. **Statement (a)**: "Columella auris present in middle ear of amphibians is modified hyomandibula of fishes."
- **Analysis**: The columella auris, which is found in the middle ear of amphibians, is indeed derived from the hyomandibula bone of fishes. This statement is correct.

2. **Statement (b)**: "Reptiles lay cleidoic eggs."
- **Analysis**: Cleidoic eggs, also known as amniotic eggs, are characteristic of reptiles and birds. This statement is also correct.

3. **Statement (c)**: "Sphenodon is a connecting link between amphibians and reptiles."
- **Analysis**: Sphenodon, commonly known as the tuatara, is considered a living fossil and is indeed regarded as a connecting link between amphibians and reptiles. This statement is correct.

4. **Statement (d)**: "Panthera tigris is an extinct animal of India."
- **Analysis**: Panthera tigris, commonly known as the tiger, is not extinct; it is an endangered species and the national animal of India. Therefore, this statement is incorrect.

### Conclusion:
The correct statements are:
- (a) Columella auris present in middle ear of amphibians is modified hyomandibula of fishes.
- (b) Reptiles lay cleidoic eggs.
- (c) Sphenodon is a connecting link between amphibians and reptiles.

Thus, the correct answer is statements (a), (b), and (c).