Across
- 1. between cattle and goats on pasture
- 6. synthetic insecticide
- 7. substances that cause pollution
- 9. between lice and head hairs
- 10. between sharks and remora
- 13. of mosquitoes and lizards
Down
- 1. between host plant and orchid
- 2. cutting down forests
- 3. the covering of the water surface by algae
- 4. relationship between bean roots and Rhizobium bacteria
- 5. produced from refrigeration equipment
- 8. chemical element with the symbol Pb
- 11. a gas that can cause global warming from manure
- 12. gas produced from animal faeces mixed with vegetable waste