Malcolm had always heard that plants grow better if you talk to them. He purchased 10 of the same kind of plant, measured the height of each one, and made two groups of plants that he kept in similar conditions. He talked to one group for half an hour each day but did not talk to the other group. After three weeks, he measured and recorded the height of the plants What is the independent variable? A the height of the plants after three weeks b talking or not talking to the plants c 2 different groups of the same plant d 10 plants