Which of the following characteristics describes the structure of the cuticle?

The cuticle, which is the outermost layer of the hair shaft, is characterized as hard and protective. It serves as the first line of defense for the hair, shielding the inner layers from environmental damage, chemical treatments, and physical wear. The structural integrity provided by the cuticle is crucial for maintaining the overall health and shine of the hair.

This protective function is vital because the cuticle's overlapping scales help to prevent moisture loss and keep harmful substances from penetrating the hair shaft. A strong cuticle enhances the durability of hair, making it more resilient against damage from heat styling, harsh weather, and other external aggressors.

Understanding the properties of the cuticle and its role in protecting hair is essential for hair care and treatment, emphasizing that maintaining cuticle health is key to achieving and preserving beautiful, strong hair.