He is a world-renowned scholar.

Geology is a study that elucidates the history of the Earth.

He is majoring in geology.

He always likes to be pedantic, explaining things down to the smallest detail.

He is a renowned economist who has written many important papers.

He is world-famous as an entomologist.

He is a renowned anthropologist, traveling around the world to study human cultures.

My father is an ichthyologist and has a deep knowledge about marine life.

He is a renowned political scientist who has written many important papers.

He is known as a government scholar.