Please answer the following question: Question: "The heterogenous and hygroscopic material is made of?"  Context: "Wood is a heterogeneous, hygroscopic, cellular and anisotropic material. It consists of cells, and the cell walls are composed of micro-fibrils of cellulose (40% – 50%) and hemicellulose (15% – 25%) impregnated with lignin (15% – 30%)."  Answer:
Answer:
cells