AP Environmental Science

Answer: D - In the cropland in use in the United States today, lost one-third of its original topsoil has been lost.

Key Takeaway: The topsoil is where most of the highly-nutritious organic material within the soil is concentrated. Plants usually concentrate their roots in the topsoil and it is where they generally get their nutrients, so it is highly important to the agricultural health of the land. Yet through poor soil management and activities like farming, logging, and development, a great deal of the topsoil has actually been lost through erosion.