2) Which of these would best explain why the microbial population begins to decrease after a period of time?
A) organisms moved away to find new mates
B)
extra food was introduced into the area
the graph actually never shows the population
decreasing
D)
organisms began to die as the population was larger
than could be supported by the limiting factors

c. heat from the poles back down towards the equator.

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.