Soil is composed of various materials, such as gravel, sand, silt, clay, and organic material. each of these substances creates a variety of different soil conditions. different soil compositions have different properties, which affect water capacity. one of these soil properties is grain size. gravel is greater than 2 mmsand is 0.5 - 2.0 mmsilt is 0.002 - 0.005 mmclay is less than 0.002 mmanswer these questions. a. a soil composed of which particle on the chart would be least effective in allowing water to pass through it? b. explain how soil grain size can affect water storage capacity in soils. c. explain why a soil composed of a combination of the grains shown would be a better soil for plants than a soil composed of just one type of grain. d. what purpose does sand serve when mixed with a soil that is made mostly of clay?