Cellulose is produced from which materials?

Cellulose is a natural polymer that primarily constitutes the cell walls of plants. It is produced as a structural component in various plant materials, predominantly from cotton fiber and wood pulp. Cotton is composed of nearly pure cellulose, making it one of the most abundant natural fibers, while wood pulp is sourced from trees and is an essential source of cellulose for various applications, including paper production.

The other options listed do not provide accurate sources of cellulose. Animal fibers, while they may contain some carbohydrates, primarily consist of proteins and are not sources of cellulose. Glass and metal alloys are inanimate materials that do not contain organic compounds like cellulose. Corn starch and wheat bran, although they contain carbohydrates, do not produce cellulose; instead, they largely consist of different forms of starches and fibers that are not classified as cellulose. Thus, the choice highlighting cotton fiber and wood pulp accurately represents the primary sources of cellulose.