Week 2 Homework: Choose your element of the week and brief discussion

Oxygen

We need it, but it's very poisonous

Ａｃｃｏｒｄｉｎｇ　ｔｏ　ｔｈｅ　Encyclopedia Britannica,  100% of dead people died within 150 years by inhaling oxygen.

All human being eventually die if we keep breathing...