Across
- 3. The only planet that spins clockwise
- 6. To rise and fall with no regular pattern
- 9. Specialist medical subject involving oral examinations
- 10. Scientific study of the animal kingdom
- 11. Gaseous element used in illuminated signs and lights
- 12. A large book involving subject with many unknowns
Down
- 1. Force that attracts a body towards the centre of the earth
- 2. Compound that is the main component of cane sugar
- 4. Mixture of metals
- 5. Oxygen at room temperature
- 7. Light bulb inventor
- 8. The hole in this layer of the atmosphere causes great concern