Final answer:
The factor not leading to the Dust Bowl was decreasing American demand for farm produce. The actual causes included overcultivation, poor farming techniques, and unfavorable weather conditions, which resulted in severe dust storms in the 1930s.
Step-by-step explanation:
The correct option : b
The Dust Bowl was an environmental catastrophe that affected the Great Plains of the United States during the 1930s. The primary causes of the Dust Bowl included previous overcultivation of farmland and poor farming techniques, especially pertaining to irrigation and crop rotation. These practices depleted the nutrients in the soil and compromised its structure, making it vulnerable to the forces of the wind. Moreover, the region experienced unfavorable weather conditions, such as drought, which exacerbated the situation by further drying out the soil, thus creating the dust storms that characterized the period.
However, decreasing American demand for farm produce was not a factor in creating the conditions for the Dust Bowl. In fact, the economic demand for crops during the 1920s had caused an agricultural boom, which ultimately led to overproduction and the subsequent overcultivation that was instrumental in causing the Dust Bowl.