Silicon dioxide is a major component of glass and ceramics.

The formation of a mountain requires millions of years.

He formed a new team.

What is this material made of?

He is majoring in chemistry at university.

Nitrous oxide is one cause of air pollution.

He is an expert in chemistry.

Liquid oxygen is often used as rocket fuel.

She decided to undergo facial reconstructive surgery.

He is dedicated to the study of organogenesis.