Where would we be without our jeans? They have been the go-to pants for many people for decades, and they are still as popular as ever. Jeans are made of denim, a type of cotton fabric. Cotton is a soft, fluffy fiber that grows in a protective case around the seeds of cotton plants. The fiber is almost pure cellulose. Cellulose is the single most abundant mslsec.comchemical compound found in Earth”s living things and one of several types of carbohydrates.