'Y' is a man-made fibre obtained from a natural source. What could be 'Y'?

Textile fibres are classified as natural (obtained directly from a plant or animal source with no chemical processing, e.g. cotton, wool, jute) or man-made. Man-made fibres split further into fully synthetic fibres (built up entirely from petrochemical monomers) and semi-synthetic fibres (produced by chemically processing a natural polymer, such as cellulose from wood pulp, into a new fibre).

Rayon is manufactured by chemically treating cellulose extracted from wood pulp (a natural source) to spin continuous filaments; because of its silky lustre it is also known as 'artificial silk'. It is therefore man-made through industrial processing yet derived from a natural raw material — exactly matching both parts of the description of 'Y'.

• Nylon is produced entirely from petrochemical-derived polyamide monomers, with no natural raw material used at any stage.

• Acrylic is produced entirely from petrochemical-derived polyacrylonitrile, again with no natural starting material.

• Jute is a natural fibre extracted directly from the stem of the jute plant with no chemical processing at all, so it is not man-made.

Since only Rayon combines an industrial (man-made) manufacturing process with a natural raw material (cellulose), Y is Rayon.