Final answer:
The independent variable in Valerie's experiment is the amount of water added, the dependent variable is the plant height, and the control group is cup 1 with 0 ml of water.
Step-by-step explanation:
In Valerie's experiment, the independent variable is the amount of water added to each cup, and the dependent variable is the height of the plant.
The constant variable is the type of plant and the 100 grams of soil added to each cup.
To determine the control group, we look at the cup that does not receive any water. In this case, cup 1 (with 0 ml of water) is the control group.