A powder derived from the North American Echinacea flower, which has been effective in preventing colds, is grown by many small farmers out West. Select one of the following answer choices A A powder derived from the North American Echinacea flower, which has been effective in preventing colds, B A derivative, which has been effective in preventing colds, of North American Echinea flower, C North American Echinacea flower derivative, which has been effective in preventing colds D The North American Echinacea flower has a derivative which has been effective in preventing colds, that E The North American Echinacea flower, a derivative of which has been effective in preventing colds, Submit Log in or register to post comments