He always proactively suggests new ideas.

His behavior was not suitable for his position.

He learned the style of the painting to imitate the ancient artist.

Keiko is my best friend.

Radioactive elements are produced in nature and scientific experiments.

Stoichiometry is a method for calculating the amount of substances in a chemical reaction.

Chemotransmitters play an important role in the transmission of information between nerve cells.

No chemical flavoring is used in this ramen at all.

My company specializes in the manufacture of fine chemicals.

The concept of chemical equivalent is essential for understanding chemical reactions.