Across
- 4. a naturally occurring substances from which metals were extracted
- 5. chemical preparations that provide immunity from a disease.
- 7. a Scottish scientist who discovered nitrogen.
Down
- 1. chemicals that are used to protect the crops from harmful pests
- 2. a person who studies and gains specialization in chemistry.
- 3. a chemical that are used to prevent wastage of food by microbial growth.
- 6. a substance made by combining two or more than two metals to resist corrosion.