Question

Give reasons for the following .a.bark of a tree is impervious to gases and water

Answer 1

as a tree gets older it undergoes certain changes . a secondary meristem replaces the epidermis and the outer cells are cut off from this layer. it leads to formation of several layer thick cork which is made of dead cells which are compactly arranged without intercellular space. other than this there is a chemical known as suberin present which makes bark of tree impervious to water and gases