Answer: "Type of fertilizer used on crops" and "Amount of sunlight a plant receives" are both independent variables.
Explanation: In an experiment, an independent variable is the variable typically being controlled and changed in an experiment to view its effects on the dependent variable. Meanwhile, the dependent variable is the variable that is being collected and measured throughout the experiment.
The amount of sunlight and the type of fertilizer are independent variables since these variables can be modified and controlled. In addition, these variables can also have an effect on dependent variables such as plant growth rate and final height or crops. On the other hand, the final height of plants and their growth rates are considered dependent variables since these variables are much more difficult to control and modify. Rather, these variables tend to be measured and observed instead.