Akiko is my best friend.

Arisa is my best friend.

He is suffering from a subacute illness.

This species has different characteristics depending on its subgroup.

This airplane flies at subsonic speed.

Hypochlorous acid is a hypo compound of chlorine.

He is suffering from combat stress reaction.

He understands the meaning of the proverb 'Teaching is half learning', which means that teaching leads to one's own learning.

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.