Across
- 3. an animal that eats other animals
- 4. any organism that can produce its own food
- 6. a living thing
- 8. a substance that living things need to function and grow
- 9. a gas found in Earth's atmosphere
- 10. cell structures used for photosynthesis
- 14. an animal that eats only plants
- 17. one of the gases in Earth's air
- 19. to act upon one another
Down
- 1. an animal that eats plants and other animals
- 2. a way to trace energy between organisms
- 4. the process by which plants make food from light
- 5. a green material in plant leaves and stems
- 7. organisms that feed on plants and other animals
- 11. any organism that eats another organism
- 12. any organism that is eaten by another organism
- 13. the air, water and organisms surrounding a given organism
- 15. a sugar that cells use for energy
- 16. web a group of food chains that are all connected
- 18. a collection of living things and the environment they live in