The function of a root hair is to View Available Hint(s) The function of a root hair is to increase the surface area available for absorption in plant roots. serve as a waxy barrier that allows plants to be selective about what enters the xylem. prevent water and soil nutrients from moving through the cytoplasm of root cells into the root. prevent water and soil nutrients from moving through cell walls into the root. allow water to evaporate from plant leaves in a process called transpiration.