The number of active hair follicles per square inch on the scalp refers to:

• A. Color
• B. Texture
• C. Density
• D. Porosity

Answer: (C)

Density is about how many hair follicles actually grow in a given area of the scalp. When we refer to active follicles per square inch, we’re measuring how full the scalp appears in that spot. This is different from color (which is about pigment), texture (the thickness or feel of each strand), and porosity (how easily moisture moves into the hair). So, the number of active follicles per square inch directly describes density, indicating how lush or sparse the hair in that area will look. Higher density means a fuller appearance; lower density means the scalp shows through more, influencing styling choices and how products or techniques are used to create volume.