Final answer:
The subject of this question is Cosmetology. The sliding thinning method is used to reduce volume and create movement in the hair.
Step-by-step explanation:
The subject of this question is Cosmetology. Specifically, the technique being described is the sliding thinning method used in hair cutting.
By partially opening the blades of the shears, a hairdresser can reduce volume and create movement in thinning hair. This method is commonly taught in cosmetology schools and is used by professionals in the beauty industry.
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