Answer:
Explanation:Energy flow and nutrient circulation are the major functions of the ecosystem.
Energy is lost as heat forever in terms of the usefulness of the system. On the other hand, nutrients of food matter never get used up. They can be recycled again and again indefinitely.
Carbon, hydrogen, oxygen, nitrogen and phosphorus as elements and compounds makeup 97% of the mass of our bodies and are more than 95% of the mass of all living organisms.
In addition to these, about 15 to 25 other elements are needed in some form for the survival and good health of plants and animals.
These elements or mineral nutrients are always in circulation moving from non-living to living and then back to the non-living components of the ecosystem in a more or less circular fashion.
This circular fashion is known as biogeochemical cycling (bio for living; geo for atmosphere).
Among the most important nutrient cycles are the carbon nutrient cycle and the nitrogen nutrient cycle.
There are many other nutrient cycles that are important in ecology, including a large number of trace mineral nutrient cycles.