The hair on the back of his arms stood up in reaction.

I was a second or two late in my reaction.

What do you mean by It isn't used in the reaction?

"I don't get lost in my own personal reaction to what people are saying."

Usually, only the overall change can be seen in a reaction.

This might one day play a powerful role in the reaction against the president.

So that the basic change was not in reaction to 9/11.

She took a deep breath in reaction to the past minutes.

She let out a short laugh and looked off to the side in reaction before meeting his eyes again.

After an active site has been involved in a reaction, it can be used again.