Explanation:Winnowing:This method of separating components of a mixture is called winnowing.Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air.This method is commonly used by farmers to separate lighter husk particles from heavier seeds of grain.In the household women also use this process for separating grain from the husk.The husk particles are carried away by the wind.The seeds of grain get separated and form a heap near the platform for winnowing.The separated husk is used for many purposes such as fodder for cattle.Thus, In villages, it is common to observe how women at home remove the husk from the grain. This method is known as Winnowing.Additional InformationSieving:Sieving allows the fine flour particles to pass through the holes of the sieve while the bigger impurities remain on the sieve.In a flour mill, impurities like husk and stones are removed from wheat before grinding it.Usually, a bagful of wheat is poured into a slanting sieve.The sieving removes pieces of stones, stalk and husk that may still remain with wheat after threshing and winnowing.At the construction site sieving is used to separate pebbles and stones from sand.Handpicking:This method of handpicking can be used for separating slightly larger sized impurities like pieces of dirt, stone, and husk from wheat, rice or pulses.The quantity of such impurities is usually not very large.In such situations, we find that handpicking is a convenient method of separating substances.Threshing:The process that is used to separate the grain from stalks etc, is threshing.In this process, the stalks are beaten to free the grain seeds.Sometimes, threshing is done with the help of bullocks.Machines are also used to thresh large quantities of grain.