Cathy wanted to find out what amount of water plants need to grow the tallest. Cathy got 10 sunflower seeds and planted them each in their own pot with the same kind and amount of soil. She then placed them all in the same place so they would get equal amounts of sunlight. The only thing Cathy changes was for plants 1 and 2, she gave no water, for plants 3 and 4, she gave them 2mL of water a day, for plants 5 and 6, she gave them 3mL of water a day, for plants 7 and 8, she gave them 4mL of water a day, for plants 9 and 10, she gave them 5 mL of water a day. Cathy measure the heights of the plants every Friday for 6 months. A. What is the independent variable? B. What is the dependent variable? C. Which two plants serve as the control for this experiment? D. What are come constants in Cathy's experiment?