Answer:
Independent variable: amount of water
Dependent variable: growth of the plant
Explanation:
In the statement "Julie notices that her plant grows one inch for every liter of water that it receives" it is implied that the growth of the plant is related proportionally to the amount of water it receives.
We know the amount of growth in function of the amount of water
The dependant variable, the result, is the growth of the plant.
Then, the independent variable is the amount of water, as it is the input to calculate the amount of growth.