Final answer:
Loess is primarily composed of silt-sized particles of fertile topsoil that has been stripped from the land by wind.
Step-by-step explanation:
Loess is a dusty yellow-colored soil that is primarily composed of silt-sized particles and is typically deposited by the wind. Historical ecological events such as the Dust Bowl in the mid-1930s highlighted the importance of soil and wind erosion. During this period, the Southern Great Plains in the United States suffered from severe drought and poor farming practices, which led to the crippling of the land's inherent protective mechanisms. Natural vegetation that once held the topsoil in place with deep root structures was replaced by extensive farmland, making the soil susceptible to erosion. Hence, the loess often consists of fertile topsoil that has been stripped from the land and redistributed by the wind.