Three batches of radish seeds, each with a starting weight of 1.5 grams (g, dry) were placed in Petri dishes and provided with light or water or both. After 1 week, the material in each dish was dried and weighed. The resulting weights were: 1) Light, no water 1.48 g; 2) light and water, 3.28 g; 3) no light, water 1.17 g.