Which of the following is a primary factor that influences soil formation?

Climate is a primary factor influencing soil formation because it affects the physical, chemical, and biological processes that contribute to soil development. Climate determines the amount of precipitation, temperature variations, and seasonal changes in weather, all of which play significant roles in weathering of rocks and organic matter accumulation.

In warm, moist climates, for example, weathering processes are accelerated, leading to more rapid soil formation. Additionally, climate influences vegetation types, which can affect organic matter input and further modify the soil structure and nutrient content. The interactions of climate with topographic features and the geological parent material are crucial in shaping the resulting soil characteristics and profiles.

While vegetation type, soil pH, and animal activity also influence soil properties, they are often considered secondary factors. Vegetation type can influence organic matter contributions and erosion rates, but it is largely determined by climate. Soil pH is a property resulting from the combination of different soil-forming factors, including climate, and while animal activity can impact soil structure and the distribution of organic materials, these activities are often mediated by climatic conditions. Hence, climate stands out as the foundational element driving the soil formation process.