Under what circumstances would a food pyramid be a more useful model than a food chain?

Food pyramid represents optimal number of food which is to be eaten each day from each basic food group where as food chain depicts the relation between producer and consumers.

Explanation:

Food pyramid is first introduced by USDA (United States Department of Agriculture) in Sweden in 1974.

Food Pyramid is design to make easy healthy eating where corret amount of nutritions like protein, fat, carbohydrate, vitamin, minerals are obtained from food.

It provides corret range of calories,essential vitamins,minerals etc.

Whereas, the disadvantage of food chain is that it gives information about qualitative info but is unable to provide quantitative info.

instead of copying and pasting things off of tests or work done on computer which im sure you did, try and read over the question carefully

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.