Across
- 3. A chemical element essential for the growth of living organisms.
- 8. Depending on each other; organisms in an ecosystem rely on each other.
- 10. Substances formed as a result of a chemical reaction.
- 12. A process that changes one set of chemicals into another.
Down
- 1. Relationships where both parties benefit.
- 2. The variety of life in a particular habitat or ecosystem.
- 4. A gas essential for the respiration of many organisms.
- 5. Substances present at the beginning of a chemical reaction.
- 6. An animal that is hunted and eaten by other animals.
- 7. An animal that hunts and eats other animals.
- 9. Related to water; living or growing in water.
- 11. A gas that plants use in photosynthesis and animals produce during respiration.