Across
- 3. outermost layer of the earth
- 4. also found in urea and alkaloids
- 6. core innermost layer of the earth
- 7. hardest metal in the world
- 9. helps in preventing soil erosion
Down
- 1. constitutes up to 21% of the earth
- 2. dioxide constitutes up to 90% of Venus and mars
- 5. constitutes up to 78% of the earth
- 8. one of the expensive metal