Final answer:
Bleaching is the most long-lasting hair color treatment because it changes the root of the hair permanently and prevents the color from returning once removed.
Step-by-step explanation:
Bleaching is the most long-lasting of all hair color treatments because it is generally left on the hair longer than other treatments. When hair is bleached, the bleach changes the root of the hair permanently by breaking down the natural melanin pigments. This process lightens the hair and prevents the color from returning once it is removed. However, it is important to note that bleaching can damage the hair, so it is essential to take proper care of the hair after bleaching.
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