Which choice below describes a feature of grassland that explains why its remnants are concentrated in arid regions of North America and central Asia?

• A. Grassland is often consumed by fire.
• B. Large grazers, such as bison and wild horses, have depleted grassland.
• C. Woody shrubs and trees have taken over in areas that receive more precipitation.
• D. Grassland has been found to be a good source of minerals and oil.
• E. The soil is fertile, and most grassland has been converted to farmland.

Answer: (E)

Verified step by step guidance

1. Understand the characteristics of grasslands: Grasslands are ecosystems dominated by grasses and have few trees or shrubs. They are typically found in regions with moderate rainfall, which is not enough to support forests.
2. Consider the impact of precipitation: In areas with more precipitation, woody shrubs and trees can take over, transforming the grassland into a different type of ecosystem. This explains why grasslands are more prevalent in arid regions where there is less competition from trees.
3. Evaluate the role of fire: Grasslands are adapted to periodic fires, which help maintain the ecosystem by preventing the encroachment of woody plants. However, this does not explain their concentration in arid regions.
4. Assess the impact of large grazers: While large grazers can affect grassland ecosystems, their presence does not specifically explain the concentration of grasslands in arid regions.
5. Analyze human impact: The fertility of grassland soil makes it ideal for agriculture. As a result, many grasslands have been converted to farmland, especially in more fertile and less arid regions, leaving remnants in less suitable areas for farming, such as arid regions.