He is an expert in ichthyology and has a deep knowledge of marine life.

He is good at solving algebra problems.

He is majoring in economics.

He is an expert in bacteriology.

He is majoring in zoology at university.

In geology, morphology is the field that studies the shape and structure of the terrain.

Geomorphology is the science that studies the surface shape of the earth.

He is an expert in pathology.

He is an expert in anthropology.

He is an expert in virology.