Oil is an important element of the world economy.

I saw a wagtail in the park.

In biology, neoteny refers to the phenomenon where the adult retains the form of the juvenile.

He is suffering from combat stress reaction.

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.

This road is made of crushed stone.