Section and Chapter titles describe broad categories of goods, while headings and subheadings describe products in more detail. Generally, HS sections and chapters are arranged in order of a product's degree of manufacture or in terms of its technological complexity. Natural commodities, such as live animals and vegetables, for example, are described in the early sections of the HS, whereas more evolved goods such as machinery and precision instruments are described in later sections. Chapters within the individual sections are also usually organized in order of complexity or degree of manufacture. For example, within Section X ("Pulp of wood or of other fibrous cellulosic material; Recovered (waste and scrap) paper or paperboard; Paper and paperboard and articles thereof"), Chapter 47 provides for "pulp of wood or of other fibrous cellulosic materials", whereas Chapter 49 covers "printed books, newspapers, and other printed matter". Finally, the headings within individual Chapters follow a similar order. For example, the first heading in Chapter 50 ("Silk") provides for "silk worm cocoons" while articles made of silk are covered by the chapter's later headings.