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