Which skin-care ingredient functions as a HUMECTANT by drawing water from the air and from deeper skin layers to the surface?
a.Zinc oxide
b.Glycerin
c.Benzoyl peroxide
d.Mineral oil
Explanation
Glycerin is a classic humectant; its hydroxyl groups bind water molecules and pull them toward the stratum corneum. Mineral oil is an occlusive, zinc oxide is a physical sunscreen, and benzoyl peroxide is an acne-fighting oxidizer.
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