Polymer used as a substitute for wool (polyacrylonitrile)

The same question, asked 2 times: 16 May 2023 S1, 25 Apr 2025 S2. Every wording below, oldest first.

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Question 1
16 May 2023 S1
68 $Which from following polymers is used as substitute for wool?$
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Question 2
25 Apr 2025 S2
59 $Which from following polymers is used as wool substitute?$
Tap an option to check your answer.