When a reaction affects the rate of other reactions, which is not normal circumstances, then this phenomenon is known as ______.

When one chemical reaction causes another reaction in the same system to occur or proceed faster than it normally would, the phenomenon is properly termed an induced reaction or chemical induction. The reaction producing the effect is the inducing reaction, while the affected reaction is the induced reaction. The effect generally arises because an intermediate or product of the first reaction participates in the second reaction. Unlike a catalyst, the inducing substance may be consumed during the process. Chemical induction is commonly associated with oxidation-reduction and chain reactions.