Q1: Soil classification of composite soils, exclusively based on the particle size distribution, is known

ANS:B - textural classification

The classification of soil exclusively based on particle size and their percentage distribution is known as a textural classification system. This system specifically names the soil depending on the percentage of sand, silt and clay. The triangular charts are used to classify soil by this system.

So given answer is correct. Textural classification is exclusively based on particle size distribution while hrb classification is based on particle size composition and plasticity characteristics. Soil texture analysis is the measurement of the proportions of the various sizes of the soil particles. The three major groups of soil particles are sand, silt and clay. The size measured for the particles change depending upon which system is used for defining soil particle size classification.

The following are the four particle size classification systems that AGVISE Laboratories use: USDA, International (ISSS), ADAS, and W.German BBA.