Katherine wants to investigate if the time of day a plant is watered affects the growth of the plant. She waters the same type of plants with the same amount of water at the same time in the morning. The plants are sitting in the same location and get the same amount of sunlight. Which variable is missing from the experiment?

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.