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.
All animals need oxygen from the air to use the energy that is in the food they eat. Plants need carbon dioxide in order to make food. Water vapor makes clouds and therefore rain, possible. Nitrogen from the air is used by bacteria on plant roots. The bacteria change nitrogen into materials that plants use to grow.