It is important to understand the importance of health.

Please use the emergency stairs in case of a fire.

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

This reaction occurs through a chemical process.

He is an excellent chemist who made many discoveries.

He is an expert in petrochemistry.

It's difficult to decipher this chemical equation.

Understanding chemical equations is difficult.

He is an expert in chemical analysis.

We are growing vegetables without using chemical fertilizers.