My country is blessed with beautiful nature.

My country is Japan.

I learned about the reaction of nitrous acid in chemistry class.

Ayu 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.

This bird is a subspecies that only inhabits specific regions.

In biology, a subkingdom is one of the large units in taxonomy.