题目

Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.     This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over the next several centuries as a result of a longer fire seasMake sure to put dangerous things in the place which the children can't________. [      ]A. create  B. approach C. defend    D. preserve