Turning in at her street, Dominique saw six fire trucks in front of her apartment building. Her heart beat wildly until someone yelled, "Just a false alarm." Her pulse then began to return to normal, due to the action of her nervous system.

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.