When organisms give off waste or decompose back in to the are both released back into the soil.

phosphorus
b. nitrogen
c. nitrogen / phosphorus

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.

maybe because its impossible for balloons to lift a whole entire house.

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.