Across
- 3. Historically considered the longest river in the world
- 7. The largest river by discharge volume flowing through South America
- 9. A colorless gas that is the life-supporting component of the air
- 11. A stable subatomic particle with a positive electric charge
- 12. The positively charged central core of an atom
- 13. The highest mountain above sea level located in the Himalayas
Down
- 1. The largest hot desert in the world covering much of North Africa
- 2. The hardest naturally occurring substance found on Earth
- 4. The capital city of Australia
- 5. The famous iron lattice tower located in Paris France
- 6. A particle representing a quantum of light or other electromagnetic radiation
- 8. A cloud of gas and dust in outer space
- 10. The force that attracts a body toward the center of the earth