Combinatorial mathematics is a branch of mathematics that studies the combinations of things.

I am majoring in phonetics at university.

I study classical language every day.

He is majoring in folkloristics at university.

He is an expert in tidology, studying the fluctuations of the sea's tides.

He is active as a researcher in futurology.

This chemotransmitter plays a crucial role in transmitting information between nerve cells.

He is an expert in nuclear physics.

He went to school with his new schoolbag.

He is an expert in enzymology and conducts many researches.