What type of cosmetic product is used to enhance the eyelashes?

Mascara is specifically designed to enhance the eyelashes by darkening, thickening, and lengthening them. This cosmetic product typically contains pigments, waxes, and oils that help to achieve a more voluminous and defined look for the lashes. The application of mascara can transform the eyes, making them appear more prominent and expressive.

Eyeliner, while also used on the eyes, is focused on defining the lash line and enhancing the shape of the eyes rather than the eyelashes themselves. Eye shadow adds color to the eyelids and can create depth and dimension but does not have the specific function of enhancing the eyelashes. Concealer is used to cover blemishes and imperfections on the skin, particularly around the eyes, but does not contribute to eyelash enhancement. Thus, mascara is the most appropriate choice for the purpose of enhancing eyelashes.