A teacher makes the analogy that stem cell research did for medicine what the Internet did for communication. What is meant by this analogy? Stem cells allow for communication between cells. Stem cells were a huge leap in technology that opened many doors. Stem cells were a setback in technology that restricted opportunities. Stem cell information is stored in databases online.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus

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.