Question

Among cellulose, chitin and lignin-- which one is most resistant to decay?

Answer 1

Lignin is most resistant to decay among the three organic materials mentioned here.

Explanation:

Among the cellulose, chitin and lignin, lignin is resistant to decay. It is deposited on the cell wall of mature plant cells. Deposition of lignin leads to death of the cells. Xylem vessels and tracheids are composed of lignin.

Please note that 'most resistant' does not mean 'nonbiodegradable'; lignin is mainly present in wood and wood decays very very slowly. Water content of the wood and moisture in atmosphere, both are important factors to enhance the rate of decomposition by microbes/fungi.