Protecting the planet is important—a lesson Hilary Duff and her youngsters know well. As the cover star of Parents' April issue along with her 7-year-old son, Luca, and 1-year-old daughter, Banks, the Younger actress naturally got to talking about raising her family with ex Mike Comrie and husband Matthew Koma, notably their strengthened focus on the environment. After she and her son saw a video of a turtle getting a straw pulled out of its nose, the image spurred the actress to seek a