Pre-lab work
1. design an experiment: what is the independent variable in this experiment (i. e., the
variable that you manipulate)?

The independent variable would be the variable that you are testing. For example, if you are testing whether plants will continue to grow in the presence of light. You will set up an experiment where plants are placed under a light source and other plants are placed in a dark room etc. In this case, presence of light is thus an independent variable.