You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between them?

The arrangement of primary xylem (protoxylem) is used to distinguish roots from stems.In roots, the protoxylem is toward the periphery and metaxylem is toward the center (Exarch).In stems, the protoxylem is toward the center and metaxylem is toward the periphery (Endarch).