Image credit: twitter.com
Let's know how,
It was greatly debated by the scientists that how exactly genes control the shape of hair. Scientists once thought that the curliness of the hairs was determined by the individual hair shafts, but have since discovered the shape of the follicle (the part of skin that grows the hair) determines both the angle it grows in and the shape of the hair with respect to the scalp.
Curly hairs have elongated oval shape and sharp angles. The curly hairs tends to be much drier that straight hairs. It is easier for the oils secreted from the scalp to travel down the shaft of the straight hair thana curly one because of it the curl hairs often turns into frizzy hairs.
And everyone with the curly hairs know that (like me) in the humid climate make the hairs more curlier or fuzzier. The reason behind it is the hair fibre absorbs the water and forces the shaft to revert to its original (curlier) structure.
This is the reason behind having the curly hairs.
Comment your questions which you want to be answered.
