Concept:Soil structure describes how individual soil particles are grouped or arranged in the soil.
Explanation:Soil particles like sand, silt, and clay do not exist separately in natural soil.
They are held together in clumps or blocks known as aggregates or peds.
The arrangement of these particles into such aggregates is called soil structure.
This structure affects water movement, air circulation, root growth, and nutrient availability.
Option A refers to soil texture, not structure.
Options B and C describe soil properties influenced by structure, but they do not define it.
Therefore, the correct definition is the arrangement of soil particles into aggregates.
Answer:D. arrangement of soil particles into aggregates.