But notice the difference in the form his reaction takes.

Had it been plutonium, a nuclear reaction would have taken place.

Why do these particular reactions, and no others, take place in cells?

The reaction takes no more than five to ten seconds.

The reaction takes between half an hour and two hours to complete.

But I don't think this reaction takes anything away from the more fundamental and fascinating experience that has led to it.

This is because the reaction, like most other reactions, takes place in a number of steps.

However, she never imagined the shape his reaction would take.

Unless people go out into the open, the reaction cannot take place.

It all depends upon the conditions under which the reaction takes place.