For questions 14-16 pick out the variables that will be needed to answer the following question: Do trees grow faster if it is wetter in the summer?

14) What is the independent variable?
a.) amount of rain
b.) no rainfall
c.) amount of growth

15) What is the dependent variable?
a.) amount of rain
b.) no rainfall
c.) amount of growth


16) What is the control?
a.) amount of rain
b.) no rainfall
c.) amount of growth