Why would it be hard to find the ideal co2 level if the light intensity were very low?

Ali hypothesized that increasing fertilizer would increase plant growth. four groups of thirty similar plants were given 0 to 15 ml of fertilizer, as shown in the graph. the change in plant height for each group over a two-week period was averaged and recorded. plant group fertilizer added (ml) avg. growth (cm) a 0 4 b 5 6 c 10 8 d 15 3 what is the best conclusion based on this data? the hypothesis was not supported because the data indicated that fertilizing plants does not improve plant growth. the hypothesis was supported; to get the best growth, use 5 milliliters of fertilizer per plant. the hypothesis was not supported; the data indicated that too much fertilizer can inhibit plant growth. the hypothesis was supported; to get the best growth, use 15 milliliters of fertilizer per plant.