He is an expert in chemistry.

It is important to understand the importance of health.

She overreacted to his words.

Nuclear reactions are used for mass production of energy.

His single word triggered a chain reaction, and everything changed.

I was surprised by his overreaction.

His body showed a rejection reaction to the transplanted organ.

He is dedicated to the study of immunochemistry.

Thermochemistry is a part of chemistry that deals with the reactions of heat and matter.

This shirt is made of chemical fiber.