How do human activities affect soils?
What will be an ideal response?
Answer: Plowing and cultivation disturb soil horizons. Agricultural activities may also reshape the land surface, which increases water runoff and decreases infiltration into the soil. Bare areas, rows of sown crops, and compacted land surfaces leave significant parts of the field exposed to water runoff and soil erosion. The loss of vegetation, especially during drought, promotes soil erosion by wind. Dry conditions and the lack of vegetation decrease soil moisture and enhance the ability of wind to pick up and move soil particles. Terracing steep slopes and planting parallel to contours diminishes water runoff. Planting continuous covers of vegetation and trees serves as a windbreak and helps retain soil moisture. Practicing "no-till" methods also decreases erosion by inhibiting water runoff and restores nutrients to the soil.
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Which of the following is true of divergent and convergent plate movement?
A) The direction of plate movement is the same. B) Convergent plate movement is less symmetrical than divergent plate movement. C) Material is destroyed with both plate movements. D) Both plates have boundaries.
The Sun tends to bloat outward by nuclear fusion, and contract due to
A. mass decrease. B. gravitation. C. nuclear fission. D. reduced gaseous pressures. E. its relatively slow spin.
All of the following would strengthen the Endangered Species Act except
a. establishing a core of survival habitats for listed species b. greatly increasing the funding for carrying out the ESA c. making the protection of endangered species on private land voluntary d. developing recovery plans for listed species more quickly e. emphasizing the protection of biological diversity and ecosystem functioning
The boundaries of a park or nature preserve are usually based on
A. how much land can be effectively managed. B. political considerations. C. animal territories. D. an entire ecosystem. E. watersheds.