Wood is a naturally occurring composite comprising cellulose fibres in a lignin and hemicellulose matrix. Carrot dietary fiber comprises mostly cellulose, with smaller proportions of hemicellulose, lignin and starch. Natural fibers are composed by microfibrils of cellulose in a matrix of hemicellulose and lignin. Their cell walls consist of cellulose, hemicellulose, and lignin. This leaves behind the fibrous parts such as cellulose, lignin and hemicellulose. Lignin and naphthalene sulfonate plasticizers are organic polymers. They frequently include boron compounds, cellulose, lignin and other plant extracts. Wood is primarily composed of xylem cells with cell walls made of cellulose and lignin. The white liquor breaks the bonds between lignin and cellulose. Most fungal lignin degradation involves secreted peroxidases. Some complexes emulate the action of various heme enzymes such as cytochrome P450, lignin peroxidase. Monolignols are phytochemicals acting as source materials for biosynthesis of both lignans and lignin. A tracheid cell wall usually contains the polymer lignin. The methyl groups come from methyl ethers present in the lignin. There are other biopolymers such as rubber, suberin, melanin, and lignin.