Answer the following question given this paragraph: 

Soil erosion is a natural occurrence. However, human activities have greatly accelerated soil erosion. In some locations, soil may now be eroding about 10 times faster than its natural rate. Since Europeans settled in the United States, approximately one-third of the topsoil has eroded away.


Q: Since europeans settled in the united states, about what percentage of topsoil has eroded away?

 Choices:

- 42 percent

- 10 percent

- 25 percent

- 33 percent

A:
33 percent
