Use the correct forms off the words in exercise I to complete the sentences.
E.g.: Many __chemicals__have been discharged into the environment and polluted it seriously.
1. _________can help farmers kill pests, but they are also harmful to environment.
2. Soil erosion and flooding are two main effects of_________.
3. _________in the area has died because there has been no rain for the last 3 months.
4. Farmers have spent much money buying_________ which is essential for a more successful crops.
5. The_________of fossil fuels is so serious that we are going to run out of it soon.
