Why do you need to classify the size of a particle

Particles larger than 2.0 mm are called gravel or stones. Most soils contain a mixture of sand, silt and clay in different proportions. The size of soil particles is important. The amount of open space between the particles influences how easily water moves through a soil and how much water the soil will hold.

answer; i believe that the correct answer is (c) on line and easily accessible; good luck