It is reasonable to assume that roads, generally, are not very good for nature, and there is good evidence to support this (1. assumption). Scientists William Laurence and Andrew Balmford point out, for example, that 95% of (2. deforestation), fires and atmospheric carbon (3. emissions) in the Brazilian Amazon occur within 50 kilometers of a road. One hundred thousand kilometers of roads now criss-cross the Amazon, and road-building there continues, often (4. illegally) contravening environmental laws. However, Laurence and Balmford believe that roads can be environmentally (5. beneficial) in agricultural areas where forests have already been cleared. Good roads ease access to markets, which improves the (6. efficiency) and profitability of farms, and tends to encourage people to stay away from vulnerable wilderness. Laurence and Balmford propose a worldwide project to establish which areas should not have roads and which areas governments should (7. prioritize) for road improvement. They believe a scheme of this kind could (8. lessen) the damage roads cause. It would be challenging, but, in Laurence and Balmford's view, influencing road development is (9. unquestionably) more practical and cost-effective than any other measure currently deployed to protect (10. crucial) ecosystems.