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.
source of carbon used by green plants. Even though there are 33,000 tons of nitrogen in the air over every acre, the nitrogen gas is so chemically stable, plants cannot directly use it as a nutri-ent. Plants readily take up and use two forms of soil nitrogen, ammonium (NH 4 +) and nitrate (NO 3 â). Other forms of nitrogen must be converted