As the members of a given generation age, their instinct of social conservation becomes stronger, which inevitably and necessarily brings them into conflict with the normal attribute of youthâinnovation. Other important theorists of the 19th century were John Stuart Mill and Wilhelm Dilthey.
Plants require more than just water and sunlight to grow. They also require many nutrients found in the soil. One of the most important nutrients required for plant growth is nitrogen. Nitrogen is used to build plant proteins and nucleic acids, including DNA.
1 Plant and animal wastes decompose, adding nitrogen to the soil. 2  Bacteria in the soil convert those forms of nitrogen into forms plants can use. 3  Plants use the nitrogen in the soil to grow.  People and animals eat the plants; then animal and plant residues return nitrogen to the soil again, completing the cycle.