Across
- 2. Smallest unit of an element
- 4. Pure substance made of one type of atom
- 7. Natural environment of an organism
- 9. Anything with mass and volume
- 10. All populations living together
- 11. Living and nonliving things interacting
- 13. All ecosystems on Earth
- 14. Role of an organism in its ecosystem
- 15. Force holding atoms together
Down
- 1. Members of one species in an area
- 3. Ability to do work
- 5. Two or more atoms chemically joined
- 6. Element forming the basis of life
- 8. Essential molecule for life
- 10. Substance made of different elements
- 12. Organisms capable of producing fertile offspring