He is an expert in theoretical physics.

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

He is an expert in biophysics.

Molecular biology is a field of study that understands life phenomena at the molecular level.

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

I am majoring in developmental biology at university.

He is an expert in algebraic geometry.

He is an expert in topology.

I am very interested in sociolinguistics.

He is majoring in oenology.