Thanks to zebra dung, cars could one day run on fuel made from old newspapers.

Today, we use mostly oil and gas to run our cars; oil and gas come from fossilized plants and animals. But fossil fuels are expensive, and there aren’t enough of them. Scientists are looking for cheaper and more plentiful fuels.

David Mullin is a biology professor at a university in New Orleans. He and his students are trying to make a fuel from plants. Plant-based fuels are called “biofuels.”

He knew that if he could break down “cellulose,” he could turn it into a fuel that could run vehicles.