Chemical Services第 78 / 100 题
The natural pH of healthy hair and skin is approximately:
a.4.5 to 5.5 (slightly acidic)
b.7.0 (neutral)
c.9.0 to 10.0 (alkaline)
d.1.0 to 2.0 (strongly acidic)
解析
Hair and skin sit in a mildly acidic range of about 4.5 to 5.5, sometimes called the acid mantle. Acid-balanced products help keep the cuticle closed and the hair healthy.
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