Question

What is the earth’s principal biological system? Why have they been and how can they be preserved?

Answer 1

Hint: Biological system is the complex network which connects the biological entities. The spans and different structure of the organism depends on the biological system. Population is the example for the biological system. It is under the macro scale property. Biological system consists of the group of organs which are working together to perform a common function. Example of the human biological system is the muscular system involved in movement.

Complete answer:
Biological is the unit of body or organism in the system. It gives only the theoretical explanation or description. Earth's biological system is classified by four types. They are forests, grasslands, crop lands and fisheries. Safeguarding of the species is important so they are preserved for the future generation. These four types are the basis of the world's economic system.
Forest is the wood or brush of the ecosystem which is the group of tall trees. Terrestrial forest provides important habitats and structure for the huge diversity. It gives shelter to more than \[80\% \] of the species. It is also the source of livelihood for the human organism. To save the forest we must plant more trees around that place. People use the small amount of livelihood from the forest. Parks are discovered to protect rainforest and wildlife. Reforestation is the important thing to protect the forest.
Grasslands are made by the wide area which is covered by the grasses. They are maintained by the grazing of animals and frequent fires. There are two types in grasslands: savannas and temperate grassland. Wetlands must be protected and restored to save the grasslands. Because they are an important source of grassland. Agricultural plants are sowed in the grasslands to provide nutritional content in the field. To reduce erosion trees must be planted near the sides.
Croplands are the basis of the economic system. It provides the food and raw materials. It is available in more amounts in some of the areas. Grasslands are sometimes turning into desert and produce when the croplands will be reduced. Avoid the chemical soil and more fertilizers in the cropland. During the rotation period maintain the soil organic matter until reaching the equilibrium level. Try to avoid the erosion in the crop land by covering the crops.
Fishery is harvesting the fish or other aquatic species for raising the level. Both the fresh water and salt water fishes are protected and harvested to increase the amount in the biological system. To save the fisheries we must use eco-friendly boats. Don’t spoil the life of smaller fishes. Overfishing easily reduces the amount of fish. Fishing methods don't destroy the fishes.

Note:
The Great Barrier Reef is the largest biological system. Biological system is analysis and synthesis of species according to the modeling concept. Information science provides the data base of the living species. Biological system must be protected because everything in the world is connected. So if one of the species is destroyed then the other species which depends on it will also die. So it is important to save all the systems in nature.