In an experiment, fluoride is given to plants to test how th…

In an experiment, fluoride is given to plants to test how the chemical hinders the plants ability to perform photosynthesis. Two groups of plants are grown for one semester at Central Alabama Community College. One group of plants is given fluoride, water, 11 hours of daily sunlight, and nutrient rich soil. The second group of plants are given only water, 11 hours of daily sunlight, and nutrient rich soil, but no fluoride. At the end of the semester, the chloroplasts in the two groups of plants are extracted and tested for their ability to perform photosynthesis. The first group of plants were not able to perform photosynthesis at all. Which variable in this experiment would be considered the independent variable?