Across
- 4. contain equal number of protons but different number of neutron
- 5. a person who studies chemistry
- 7. process that helps plants involving sunlight
- 10. meaning to be intelligent
Down
- 1. the study of life
- 2. smallest unit in a chemical compound that can take part in a chemical reaction
- 3. Depression a period of time when the economic system declined sharply
- 6. a branch of science
- 8. ideas that try to explain something
- 9. a person who studies science