She is majoring in clinical psychology.

He is an expert in psychiatry.

He is known as an expert in population genetics.

He is an expert in theoretical physics.

He is an expert in phytopathology, making a significant contribution to agriculture.

He is an expert in ethology, and his research is highly regarded worldwide.

He is an expert in algebraic geometry.

He is an expert in topology.

I am very interested in sociolinguistics.

He is majoring in oenology.