Root hairs and microvilli both have a long thin shape to help with absorption (of digested food by microvilli and of water and minerals by root hairs) by giving them lots of surface area.
Work Step by Step
Review Fig. 6.8 and Fig. 35.13 to see the parallel between the shapes of root hairs and microvilli. Then review the associated text for each to see the role of surface area and the description of the role of each of those structures.