Gender roles are an important element in defining individual behavior in society.

His role is to fulfill his responsibilities as a leader.

It is important to understand the importance of health.

Organic solvents play an important role in chemical reactions.

This reaction occurs through a chemical process.

He is an excellent chemist who made many discoveries.

He is an expert in petrochemistry.

He is an expert in chemical analysis.

It's difficult to decipher this chemical equation.

Understanding chemical equations is difficult.