Feeling a little hungry? Then grab a snack and watch Bill Nye the Science Guy's episode on the Food Web. When it comes to eating, all living things depend on other living things. Take a chicken sandwich, for example. The bread came from plants. So did the lettuce and tomatoes. The cheese was made from milk, which came from a cow. To make milk, the cow had to stay alive by eating grass. The meat came from a chicken who once ate seed, and maybe the occasional bug. The animals that helped to make your sandwich depended on other living things to survive. The lettuce, grain (for the bread), and tomato got by fine on their own. Then some animal came along (you). Plants are the only big living things that don't need other living things to survive. All they need are sunlight, carbon dioxide, and water to make their own food. But it doesn't stop them from being eaten -- no way. In fact, plants are great things to eat. All animals need them in some way for food – by the way