๋ณด๋ค
์ด๋ฒคํธ
์์ฅ
ํ์ด์ง
๋
We've been doing this long before I was born and scientist now "discovering" this? ๐
๋ ๋ก๋
ํญ๋ชฉ์ ๊ตฌ๋งคํ๋ ค๊ณ ํฉ๋๋ค. ๊ณ์ํ์๊ฒ ์ต๋๊น?