Answer:1. If it is a small mixture you can use hand picking but if a bigger one, use sieving method so that small sand grains will sieve through leaving bigger pebble

2.You can boil or evaporate the water and the salt will be left behind as a solid. If you want to collect the water, you can use distillation. This works because salt has a much higher boiling point than water

3.separates molecules based on their size by filtration through gel. The gel consists of spherical beads containing pores of a specific size distribution. Separation occurs when molecules of different sizes are included or excluded from the pores within the matrix.

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