Which hair condition is often caused by a lack of moisture?

The correct answer encompasses the idea that a lack of moisture can contribute to various hair conditions. When hair lacks moisture, it may lead to frizz because the hair cuticles become rough and raised, resulting in a lack of smoothness and definition. Dry hair often lacks elasticity and may also become more prone to damage, which can manifest as split ends. While an oily scalp is typically associated with excess sebum production rather than moisture deficiency, it can still be impacted by overall hair health, as dry hair strands may cause the scalp to overcompensate by producing more oil. Thus, acknowledging that a lack of moisture can affect multiple hair conditions supports the reasoning for the answer chosen.