These structures release cells that perform neutrophil-like functions by expelling extracellular DNA, called border cells. The movement of specialized organelles within the columella cells of these structures (10[1])helps direct their growth according to the starch-statolith hypothesis. These structures can recover from damage by triggering the proliferation of stem cells located in quiescent centers. (10[1])The lengthening of cells in the zone of elongation causes most of the growth of these structures, which often (-5[1])display positive gravitropism. (10[1])These structures form symbiotic relationships with fungi (10[1])called mycorrhizae. (10[3])Material in these structures is transported to the rest of the organism through (10[1])the xylem. For 10 points, name these structures that plants use to take up nutrients and water. ■END■ (10[1])