What are the three principles of sustainability?

The three principles of sustainability are Solar Energy, Chemical Cycling, and Biodiversity.

Solar Energy: Involves the use of the sun to provide life to the plants, thereby providing life (and light and warmth) to this planet. Without the sun, or rather, solar energy produced by the sun, plants could not grow. Without plants, the consumers of said plants would not survive. This is why Solar Energy is important in regards to the principles of sustainability.

Chemical Cycling: Involves the transfer of chemicals such as nutrients and minerals from the soil and solar energy transferring to plants, then transferring to the animal that eats the plant (herbivore), transfer of the same nutrients to the animal that eats the herbivore (carnivore), and the transfer of the nutrients from the carnivore to fungi, and then the nutrients and minerals are transferred back to the soil to be recycled. Chemical Cycling involves producers (such as plants), consumers (the herbivore and carnivore) and decomposers (the fungi/decomposition of the consumer to return to the soil).

Biodiversity: The term is short for "Biological Diversity" and refers to the many variances of life on the planet, the natural habitats, and natural resources. Natural life would be animals, plants, and microorganisms. Natural habitat examples are forests, oceans, and deserts. Natural resource examples are air and water. Biodiversity, variances in species, contributes to evolution of said species, and humans rely on biodiversity to survive, just as all animals do as well, along with the planet.