What is a common cause of hair breakage?

A common cause of hair breakage can indeed include various factors, and when considering the answer that encompasses multiple causes, "all of the above" is the most comprehensive choice.

Improper brushing can lead to hair breakage as it may cause unnecessary tension on the hair strands, particularly if the hair is tangled or wet. Using the wrong brush or brushing too vigorously can contribute to weakening the hair, leading to breakage.

Excessive heat styling is another significant contributor to hair damage. Regularly using high temperatures from styling tools can strip moisture from the hair, making it dry and brittle, and ultimately more prone to breakage. Heat can weaken the protein structure of hair, resulting in weakened strands that are likely to snap.

While insufficient washing is less commonly associated with hair breakage compared to the other two, it can still play a role. Not washing the hair regularly can lead to product buildup, which can weigh hair down and impede healthy hair growth, making it more susceptible to breakage.

Thus, "all of the above" effectively summarizes a range of factors that can lead to hair breakage, highlighting the importance of proper hair care practices in maintaining healthy hair.