Why did the addition of cellulose mean “you can enjoy [ice cream] a little bit longer”? A- Cellulose made the ice cream colder, which prevented it from melting.

B- Cellulose expanded when wet, which helped the ice cream maintain its shape longer.

C- Cellulose created a mold for the ice cream to fit into.

D- Cellulose prevented air from reaching the fat in ice cream.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .

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.