Read the main idea: your community can save big, too. which choice best represents a supporting detail for this main idea? a.) it's great for watering vegetable plants and flowers around your house. i use it to fill me fish tank, even to wash the car if you want to. b.) one of the benefits of the rain barrel is that it holds that first bit off rain that's coming off your roof or driveway and prevents it from running into streams and causing erosion from high flows of water. c.) i made my own rain barrel but you can buy them pretty cheaply now. d.) for more information on how you can make your own rain barrel, visit and search for rain barrels.