An ecologist studying communities would study which of the following?A. The development of males' mating dances in a particular species of spider.B. Changes in the size of a mouse population after hawks, a main predator of mice, are introduced into the area where the mice live.C. Changes in the abundance of a particular species of frog in a portion of a rainforest over time.D. The effects of soil erosion on plant species found on the side of a mountain