Cellulose is primarily found in which part of plants?

The correct choice indicates that cellulose is primarily found in cell walls. This is because cellulose is a complex carbohydrate that serves as a structural component in the cell walls of plants. The arrangements of cellulose fibers provide rigidity and strength to the plant cells, allowing them to maintain their shape and resist external pressures.

Cellulose forms a major part of the primary and secondary cell walls in various types of plant tissues. This structural role is vital for the overall integrity of plant structures, helping plants to stand upright and withstand mechanical stresses.

While roots, leaves, and seeds contain cellulose as part of their cell walls, the specificity of the question regarding the "part" of plants highlights the cell wall as the main location where significant amounts of cellulose are present across various plant tissues. Thus, the correct answer accurately centers on the nature of cellulose's role in plant structure.