Gels are ___ cured?

Gels are cured using light, which is the correct answer to the question. This process typically involves ultraviolet (UV) light or LED light, which activates the photoinitiators in the gel formulation. These photoinitiators trigger a chemical reaction that causes the gel to harden or "cure." This method is distinct from other curing processes, such as air drying or using heat.

In contrast, heat curing involves a different set of materials that require elevated temperatures to set, while air curing depends on exposure to the atmosphere for a certain period, and water curing is not a standard method for nail gels. The unique nature of light curing allows for a quick and efficient process in nail technology, which is why understanding the importance of UV or LED light in curing gels is essential for professionals in the field.