Food Production

3. What are given to fish to prevent disease (11)
8. Living organisms to control pests (17)
10. Increases rate of photosynthesis until limited by another factor (14)
11. Needed to make nucleotides for DNA (9)
13. A chemical used to kill insects or crops which damage plants (9)
14. A substance spread on soil to help crops grow bigger and faster (10)
17. When bacteria are no longer killed by antibiotics (10)
18. Gradual build of chemical substances in an organism over its lifespan (15)
19. Transports sucrose and amino acids in plants (6)
20. Pesticide for weeds (9)

1. Increases rate of photosynthesis until enzymes denature (11)
2. Toxic substances become more concentrated in tissues moving up the food chain (16)
4. Can be controlled by adding lime to it (6)
5. Can be done to ensure high quality, fast-growing fish (17)
6. Needed to make amino acids (8)
7. What is lost at each trophies level of the food chain (6)
9. Catching fish faster than they can reproduce and grow (11)
12. What can be controlled in fish farming to reduce pollutants in flesh of the fish (12)
15. Transports water and mineral ions in plants (5)
16. Used to make chlorophyll (9)