Read the following four statements ( I - IV ) :
I. In birds , the skin is dry without any glands except the preen glands which are modified sudorific glands .
II. All mammals exclusively respire by using lungs , except dolphins.
III. Chameleon is a tree lizard with a prehensile tall and independently movable eyes.
IV. Amphibia is the only tetrapod vertebrate which has external fertilisation with no larval stage in their life cycle .
How many statements is / are correct form the above ?

Options

A. Four
B. One
C. Three
D. Two

Answer

To determine how many of the statements are correct, we will analyze each statement one by one.

### Step 1: Analyze Statement I
**Statement I:** "In birds, the skin is dry without any glands except the preen glands which are modified sudorific glands."

- **Analysis:** This statement is incorrect. While it is true that birds have dry skin, the preen glands are not modified sudorific glands (sweat glands); they are sebaceous glands that secrete oil to maintain feather health.

### Step 2: Analyze Statement II
**Statement II:** "All mammals exclusively respire by using lungs, except dolphins."

- **Analysis:** This statement is also incorrect. While most mammals do use lungs for respiration, dolphins are mammals that do use lungs, so the phrasing is misleading. There are no mammals that exclusively respire using lungs except dolphins; rather, dolphins are mammals that respire using lungs.

### Step 3: Analyze Statement III
**Statement III:** "Chameleon is a tree lizard with a prehensile tail and independently movable eyes."

- **Analysis:** This statement is correct. Chameleons are indeed known for their prehensile tails and their ability to move their eyes independently, which helps them in hunting and scanning their environment.

### Step 4: Analyze Statement IV
**Statement IV:** "Amphibia is the only tetrapod vertebrate which has external fertilization with no larval stage in their life cycle."

- **Analysis:** This statement is incorrect. While many amphibians do have external fertilization, they typically have a larval stage (like tadpoles). Additionally, there are other tetrapod vertebrates that can exhibit external fertilization, such as some fish.

### Conclusion
After analyzing all four statements, we find that:
- Statement I: Incorrect
- Statement II: Incorrect
- Statement III: Correct
- Statement IV: Incorrect

Thus, only **one statement (Statement III)** is correct.

### Final Answer
**Only 1 statement is correct.**

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