Answer:
Independent variable: amount of insecticide
Dependent variable: effects of insecticide on frogs
Step-by-step explanation:
Dependent variable in a research experiment, is the variable that is being studied, tested and measured by the researcher, while the independent variable is the variable that causes the dependent variable to change, when it is varied.
In this case, the amount of insecticides that is varied in quantity, is the independent variable that the researcher manipulates, while the independent variable is the effects caused by these varied amount of insecticide on frogs, which is tested and measured.