List 4 facts of primary succession & 4 facts of secondary succession .

-The stages of primary succession include pioneer plants (lichens and mosses), grassy stage, smaller shrubs, and trees.

-Animals begin to return when there is food there for them to eat.

- Successional dynamics following severe disturbance or removal of a pre-existing community are called secondary succession.

-An area of growth.

-A disturbance, such as a fire, starts.

-The fire destroys the vegetation.

-The fire leaves behind empty, but not destroyed soil.-

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.