In which type of textile printing is a raised, velvet-like effect produced on the printed fabric surface?

Consider the following statements regarding the factors contributing to the increased popularity of knitting in fabric manufacturing: I. The operational framework of knitting units necessitates a substantial capital investment, which is uniquely offset by the extraordinarily high productivity of the machines. II. The inherent versatility of knitting techniques and their compatibility with newly developed man-made fibers serve as major catalysts for its widespread adoption. III. The structural characteristics of knitted fabrics inherently satisfy modern consumer demands for lightweight, well-fitted, and stretchable garments. IV. The rising consumer preference for apparel that is wrinkle-resistant, easy to care for, and capable of maintaining a neat appearance during use has directly boosted the demand for knitted fabrics. Which of the statements given above are correct?

Which natural fiber is difficult to spin into yarn due to its brittle nature and is used primarily as fiberfill or stuffing?