Fill in the blanks by choosing the appropriate word/words from those given in the brackets : (Natural, synthetic, step-growth, chain-growth, natural rubber, synthetic rubber, melamine, thermo, thermosetting, addition, condensation, hydrogen bonds, van der Waals', 373-573, 543, 100, 10, benzoyl peroxide, acetyl peroxide, amide, butadiene, natrium, dimethyl terephthalate)
In fibres, the chains are held together by ..........bonds.

Explanation

To solve the question, we need to identify the type of bonds that hold the chains together in fibers. Here’s a step-by-step solution:

1. **Understanding the context**: The question pertains to fibers, which are typically made up of long chains of molecules. These chains can be held together by various types of intermolecular forces.

2. **Identifying the types of bonds**: The options provided include various types of bonds such as hydrogen bonds and van der Waals' bonds. In the context of fibers, we need to determine which type is most relevant.

3. **Recalling properties of fibers**: Fibers, especially natural ones like proteins, often have structures stabilized by hydrogen bonds. These bonds provide strength and stability to the fibrous structure.

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