4. Exercise IV

The impurities are addedimpurities are mixedimpurities are removed from any flour using a sievebeakerpaper by a process called sieving. Sieving allows the tiny flour particles to remain on the holes of the sieveremain on the sievepass through the holes of the sieve while the bigger impurities pass through the holes of the sieveremain on the sieveremain on the holes of the sieve. During the construction of a building, workers uses the rotary sand sieving machine to filterrotary machine to addsieving machine to mix the sand from stones and pebbles.