Which of the following properties affects the consistency of soil?

Density is a crucial property in determining the consistency of soil. It directly impacts how tightly packed the soil particles are, which influences both the soil's ability to hold water and its overall stability. A higher density usually means that the soil is compacted more tightly, which can decrease porosity, leading to less water retention and potentially affecting plant growth. Conversely, a lower density typically indicates more porous soil, which can hold more air and water, thereby enhancing the soil's ability to support plant life. Understanding density thus allows for better predictions about how soil will behave under various environmental conditions and its suitability for different uses.

The other properties mentioned, while they do play roles in soil characteristics, do not directly affect consistency in the same way density does. Color can provide insight into soil composition and drainage but does not indicate how the soil will behave under pressure. Pollution levels relate more to soil quality and health rather than its physical consistency. pH level affects nutrient availability and biological activity in the soil but does not influence how cohesive or loose soil is. Understanding density allows for a clearer picture of how soils will respond to various stresses, making it the more relevant factor in this context.