Across
- 4. This gas is emitted by cars, busses, planes, etc.
- 6. This can use the sun's energy to produce electricity.
- 7. Methane, Co2 and others are called ... gasses.
- 8. Using ... energy can sometimes be very easy and can be done by everyone.
Down
- 1. Some hope that new ... can help to find solutions to our problems.
- 2. Wind ... are a useful source of power close to the sea or in flat areas.
- 3. You have to ... rubbish to save the planet.
- 4. One of the biggest problems of humankind today.
- 5. The ... of air, waterways and forests is a huge issue.