Question

_________is a method in which particles are sieved through holes of the sieve.​

Answer 1

Sieving allows the fine flour particles to pass through the holes of the sieve while the bigger impurities remain in the sieve.
So sieving is the answer.

Answer 2

The aggregate should be oven-dried at high temperature before sieving to prevent lump formation of the fine particles due to moisture content, which might clog the fine sieve holes.