Final answer:
The remnants of Hertwig's epithelial root sheath persist as the cells of the internal root sheath surrounding the root of the growing hair up to the hair shaft.
Step-by-step explanation:
The remnants of Hertwig's epithelial root sheath persist as the cells of the internal root sheath surrounding the root of the growing hair up to the hair shaft. These cells are derived from the basal cells of the hair matrix.