Yamatobumi is my best friend.

He wants to learn about the life of nomads.

He played beautiful music using a pellet drum.

China adopts the principle of people's democratic dictatorship.

General relativity is a theory of physics proposed by Einstein.

Special relativity is one of the fundamental theories of physics.

This area is seriously contaminated with radioactive isotopes.

He feels dizzy when he stands up suddenly due to orthostatic hypotension.

My father was diagnosed with ankylosing spondylitis.

In organic chemistry, pyruvic acid plays an important role.