Nevada State Board of Cosmetology Practice Exam

Furrows in nails, also known as ridges, can be caused by a variety of factors including nutrition, injury and illness. While vitamin deficiencies may contribute to brittle or discolored nails, it is not the main cause of furrows. Frequent exposure to water can also lead to damaged nails, but it is not the sole cause. Careless filing can also create ridges on the nails, but it is less likely to be the main cause compared to nutrition, injury, or illness.