Final answer:
The independent variable in the experiment involving different colored lights on a group of plants is colored lights. The different colored lights are being used as the independent variable to test their effect on the growth of the plants.
Step-by-step explanation:
The independent variable in the experiment involving different colored lights on a group of plants is B) Colored lights.
The independent variable is the variable that is intentionally changed or manipulated in an experiment. In this case, the different colored lights are being used as the independent variable to test their effect on the growth of the plants. The dependent variable would be the growth of the plants.