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 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. The lengthening of cells in the zone of elongation causes (10[1])most of the growth of these structures, which often display positive gravitropism. (-5[1])These structures form symbiotic relationships with fungi called mycorrhizae. Material in these structures is transported to the rest of the organism through the xylem. (0[1])For 10 points, name these structures that plants use to take up nutrients and water. ■END■