Across
- 1. something that is dangerous and likely to cause damage
- 4. a substance that makes something less pure or makes it poisonous
- 5. the solid surface of the earth that lies under the ocean
- 8. any substance that plants or animals need in order to live and grow
- 10. a poisonous substance, especially one produced by bacteria, that causes disease
- 11. a wall built across a river that stops the river's flow and collects the water, especially to make a reservoir that provides water for an area
- 12. waste matter such as water or human urine or solid waste
- 13. able to decay naturally and in a way that is not harmful
- 14. broken or torn pieces of something larger
- 15. a circular movement in which each circle is above, below, or wider than the one before
Down
- 2. a place where especially large pieces of rubbish can be taken and left
- 3. traditional and ordinary
- 6. an area under the earth's surface where there is a large amount of oil
- 7. fuels, such as gas, coal, and oil, that were formed underground from plant and animal remains millions of years ago
- 9. the rise and fall of the sea that happens twice every day