Both science and religion (1)/ are necessary for man and for their (2)/outer and inner self respectively. (3)/ No error (4)

Explanation

To solve the question, we need to identify the error in the sentence provided. Let's break it down step by step:

1. **Identify the Parts of the Sentence**: The sentence is divided into four parts:
- Part 1: "Both science and religion"
- Part 2: "are necessary for man and for their"
- Part 3: "outer and inner self respectively."
- Part 4: "No error"

2. **Analyze Each Part**:
- **Part 1**: "Both science and religion" - This part is correct. It correctly uses "both" to refer to two subjects.
- **Part 2**: "are necessary for man and for their" - Here, we notice an error. The word "their" is plural, while "man" is singular. Therefore, we should use "his" instead of "their" to maintain singular agreement.
- **Part 3**: "outer and inner self respectively." - This part is correct. It appropriately refers to the two aspects of man (outer and inner self).
- **Part 4**: "No error" - This option is incorrect as we have identified an error in Part 2.

3. **Correct the Error**: The corrected sentence should read: "Both science and religion are necessary for man and for his outer and inner self respectively."

4. **Conclusion**: The error is in Part 2, where "their" should be replaced with "his."

**Final Answer**: The error is in Part 2.

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