They called for a boycott of the product.

Everest is the highest peak in the world.

His body showed a rejection reaction to the transplanted organ.

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

This chemical reaction is very dangerous.

She overreacted to his words.

Nuclear reactions are used for mass production of energy.

I was surprised by his overreaction.

He is an expert in medicine.

He is learning the basics of elementary learning.