Wool is a specially treated animal hair - goats, sheep, camels, llamas, etc. Scaly structure of the hair helps them well bonded to each other, making a strong thread, in addition, wool has excellent thermal insulation. The coat is waterproof and does not transmit heat, so in the summer knitwear made of natural wool person will not be hot. Wool is very versatile - you can safely winter sport in a woolen coat and not be afraid of the cold, and in summer in a dress made of fine, "summer" wool you will not be hot.
But also silk and wool have their drawbacks.
Firstly, silk heavily wrinkled. However, this property is often considered almost chic, but in this sense, the silk is not too practical. Wool, for example, almost no creases, the thing is to keep the form as long as necessary. In addition, the liquid leaves on silk fabric stains, which can only be removed with alcohol.
The main drawback of wool - rapid wear fabric.
The general lack of wool and silk - a high price. Production technology is quite costly and time-consuming, unlike synthetic fabrics, in addition, sometimes fail to distinguish from natural fabrics quality fakes.