noun 다운로드 🔗공유 머리카락과 손톱을 구성하는 단백질 The protein of which hair and nails are composed. Examples : "My hair is strong because it has a lot of keratin. " 내 머리카락은 케라틴이 많아서 튼튼하다. physiology material substance body anatomy biology AI와 채팅어휘 게임독해 연습