Lucy lives near a small pond. Lucy is studying the spread of the invasive plant called purple loosestrife near the pond. Every month for the past two years, she has counted the number of loosestrife plants near the pond. She has also counted the number of other plants, such as cattails, found at the pond over the years. What question can Lucy answer using the data she has collected? A. Do ducks like to nest in loosestrife plants more than in cattail plants? B. What is the best temperature for growing loosestrife plants and cattail plants? C. Has the number of cattails gone down as the number of loosestrife plants has gone up? D. Do songbirds eat the seeds produced by the loosestrife plants?