He is an expert in pomology and has contributed to the improvement of many fruit varieties.

He is known as the kapellmeister of a famous orchestra.

He is majoring in geology.

This reaction occurs through a chemical process.

He is majoring in economics.

He is an expert in bacteriology.

He is an expert in pathology.

I study Japanese every day.

He is an expert in virology.

He has a deep interest in teratology.