Q: What slow process is required for formation of soil?


Read this paragraph and choose the correct option from the provided answers:

Soil formation requires weathering. Where there is less weathering, soils are thinner. However, soluble minerals may be present. Where there is intense weathering, soils may be thick. Minerals and nutrients would have been washed out. Soil development takes a very long time. It may take hundreds or even thousands of years to form the fertile upper layer of soil. Soil scientists estimate that in the very best soil forming conditions, soil forms at a rate of about 1mm/year. In poor conditions, it may take thousands of years!.

 Choices:

- leaching

- digestion

- fossilization

- weathering


A:
weathering