Enviromental

1. Sustainable means using methods, systems and materials that won't deplete resources or harm natural cycles.
2. To them it means they can provide themselves with what they need.
3. As the demand for energy gets higher, it makes it harder to keep the sustainability
4. Well they can have renewable energy sources. They can live in communities with everything they need inside them. The third thing could be that they have community gardens like the one in the movie.