Apply the same amount of light to all the plants. Apply only green light to all the plants. Flash the lights to simulate a partly cloudy day. Keep the plants in darkness.
I gave my students this multiple choice question: A plant scientist is developing a new fertilizer called Hypergrow. She designs an experiment to test whether Hypergrow helps plants grow faster than Supergrow, a fertilizer already on the market. Which of the following should the scientist do with light during the experiment?

Only one answer is correct among these 4 choices:
- Apply the same amount of light to all the plants.
- Apply only green light to all the plants.
- Flash the lights to simulate a partly cloudy day.
- Keep the plants in darkness.

Could you tell me which one is correct?

Apply the same amount of light to all the plants.