A ---(1)--- is a group of individuals of the same species that mate and produce offspring. In each generation, new genotypes occur that express themselves as specific individual ---(2)---. Any factor that affects the ---(3)--- of a population can change the frequency of ---(4)---, resulting in evolution over time. Through the processes of variation and ---(5)---, new species can arise. A ---(6)--- is a population of physically similar, interbreeding organisms that do not interbreed with other such groups.

c. movement because i took the test and it lets me review my answers

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.