Which acid is derived from plants and used to exfoliate the skin?

Alpha hydroxy acids (AHAs) are derived from plant sources and are widely used in skincare for their exfoliating properties. They are natural acids that help to remove dead skin cells from the surface of the skin, promoting cell turnover and revealing a fresher complexion. Common examples of AHAs include glycolic acid, lactic acid, and citric acid, all of which are found in various fruits and milk.

The exfoliating action of alpha hydroxy acids enhances the overall texture and tone of the skin, making them popular in various skincare products and professional treatments. Their ability to dissolve the bonds between dead skin cells allows for easier shedding of these cells, which can improve issues such as dullness, uneven skin tone, and fine lines.

The other options listed do not pertain to plant-derived acids for skin exfoliation. Alkalis and sodium hydroxide are not acids at all; instead, they are bases that can be highly irritating and are primarily used in other manufacturing and cleaning processes. Glycolic acid, though a type of alpha hydroxy acid, is a specific example rather than a broader category like alpha hydroxy acids. Therefore, the best answer that encompasses the general concept of plant-derived exfoliating acids is alpha hydroxy acids.