Joann is testing soils to see which kind is best for growing marigolds. Which of the following should she do?
Plant the marigolds in the same soil, but water some plants more than others. Plant the marigolds in one kind of soil, radishes in another, and daisies in a third kind. Plant the marigolds three kinds of soil, and give them different amounts of sun. Plant the marigolds in three kinds of soil, and give them the same amounts of water and sun.