Seigai is my best friend.

Mr. Sotozono is my best friend.

Insects have an exoskeleton, which protects their body.

This medicine is made outside of the body.

He played a perfect fifth scale on the piano.

He is a perfectionist, so he is very strict about his work.

This sentence contains non-Jōyō kanji.

This sentence contains kanji not approved for regular use.

He started exercises to strengthen his abductors.

He is doing special exercises to strengthen his supinator.