A student is studying the effect of fertilizer on fruit growth. He uses 6 tomato plants, placing each in a garden where they get the same amount of sun and water. One plant is given no fertilizer, while the other 5 plants are given 5, 10, 15, 20, and 25 grams of dissolved fertilizer each day for 3 weeks. At the end of the experiment the tomato fruits are weighed.
What is the independent variable in this experiment?
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1 point
fruit weight
amount of water
amount of fertilizer
sun exposer