Q. Which of the following are correctly matched?

1. Threshing - stalks are beaten to separate grains
2. Winnowing - method of separating husk from grains
3. Hand-picking- used to separate undesirable substances
4. Sieving - used to separate solid mixtures of same size

Select the correct answer from the codes given below:
Answer: Only 1, 2, and 3
Notes: Threshing is the process in which stalks (of wheat, paddy, etc.) are beaten to separate grains from stalks, and the chaff that covers the grains. The method of separation is based on the fact that the 'stalks' of the crop plants and the 'chaff' are soft materials whereas the grains themselves are very hard. Winnowing is the method of separating husk from grains with the help of wind. This method is based on the fact that husk is very light whereas wheat grains are comparatively heavy. Hand-picking means to take out by hand. The method of hand-picking is used to separate those substances where one of the components is in small quantity. The method of hand-picking is used to separate undesirable substances such as small pieces of stones from wheat, rice and pulses. Sieving is used to separate those solid mixtures which have components of different sizes.

This question is part of UPSC Daily 20 MCQ Series Course on GKToday Android app.