Across
- 4. why does weight matter when planes are flying?
- 6. plant matter
- 7. walking is .... For the environment than cars are.
Down
- 1. how many people travel by plane per year?
- 2. which one is better for the environment:bus or plane?
- 3. which of these is a maglev train: heavy-rail or light-rail?
- 5. what do plug-in cars run on?