Why is it necessary to model the concept above?

You did not write the concept, so i will try to answer in a general way.

Why sometimes we really need to model concepts?

Well, sometimes the things are really complicated, or we just do not have the knowledge or tools to fully understand them.

Here is where the models came to be handy, we can somewhat "simplify" the things, and explain them with models.

For example, the movement of a particle as the wind pushes it can be really complex, so this can only be explained with a model.

Now, once we have a model (supported by theory and experiments) we can start to investigating furthermore in the given subject.

So for example, we could model how a given therapy acts on a given disease, and with that model, we could extrapolate the effects of the therapy in a similar disease (for example, testing how radiotherapy acts on a given tumor in some organ, can give information on how the same therapy can act on other types of tumors)

Concluding, models simplify some concepts, which allow us to understand them and work better with them

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg