He is majoring in chemistry at university.

We heat our house with natural gas.

He is an expert in chemistry.

This lake is known as a dangerous body of water.

He has mastered all the uses of the Eighteen Arms of Wushu.

The use of bioweapons is prohibited by international law.

Please use the emergency stairs in case of a fire.

Due to the earthquake, the city declared a state of emergency.

Noble gases are known for not participating in chemical reactions.

In this area, there is a shortage of noble gas supply.