The ejecta from volcanoes help to elucidate the geological history of the Earth.

Prefix notation is a notation where the operator comes before the operands.

This structure has existed for centuries.

Front vowels are pronounced using the front part of the tongue.

He is an expert in mineralogy.

He is an expert in paleontology and is researching dinosaurs.

He is an expert in nuclear physics.

In chemistry class, I learned about basic oxides.

In chemistry class, I learned about acidic oxides.

Bioweapons are a major threat to humanity.