$ The skeleton which occurs on the surface of animal body is called exoskeleton.
! Endoskeleton is formed of bones.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

To solve the question regarding the assertion and reason about exoskeletons and endoskeletons, we will follow these steps:

### Step 1: Understand the Assertion
The assertion states that "The skeleton which occurs on the surface of the animal body is called exoskeleton."
- **Analysis**: This statement is true. The exoskeleton is indeed the outer skeleton that provides support and protection to the soft tissues of certain animals.

### Step 2: Understand the Reason
The reason states that "Endoskeleton is formed of bones."
- **Analysis**: This statement is partially true. While the endoskeleton is primarily composed of bones, it also includes cartilage. Therefore, saying it is formed solely of bones is not entirely accurate.

### Step 3: Determine the Relationship Between Assertion and Reason
- The assertion is true, and the reason is partially true but incomplete because it does not mention cartilage, which is also a component of the endoskeleton.

### Step 4: Conclusion
Based on the analysis:
- The assertion is correct.
- The reason is incorrect because it does not provide a complete explanation of what an endoskeleton is.

Thus, the correct answer is: **The assertion is correct, but the reason is wrong.**

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