A scientist conducts an experiment to test the effect of light on plant growth. In each experiment, three plants of the same variety are each given 10 mL of water. One plant is exposed to full sunlight

for 8 hours, one is exposed to full sunlight for 4 hours, and one plant is kept in a dark room. Plant

height is measured after two weeks.

1.What is the independent variable in this experiment?

2.What is the group of items in the experiment in which conditions are kept the same referred to as?