Plants get it from bacteria which live associated with their roots who take atmospheric nitrogen and fixate it (nitrogen cycle). Animals can only get it by ingesting organic compounds which contain nitrogen, such as plants and other animals which have eaten plants.
Animals obtain nitrogen by eating plants which have absorbed nitrogen from the soil.
Nitrogen
eating the plants
by consuming plants or other animals
Plants can obtain a variety of things from animals. The main things are CO2 from the exhaust of mammals, and the minerals/nutrients from animals' waste. Nitrogen from chicken waste is a very good example.
Nitrogen is found in all living systems as part of the makeup of biological compounds. Animals obtain the nitrogen they need by eating plants, or by eating other animals that have eaten plants.
Plants take in nitrogen from their roots then the consumers eat the plants.
Most plants get nitrogen from fertilizers. Some plants can have a process called nitrogen fixing in which nitrogen from the is turned into ammonium compounds. Animals get their nitrogen from food, by eating plants and other animals.
Animals get nitrogen from plants.
Plants and animals die and decomposers break down their nitrogen containing molecules to ammonia. All animals get the nitrogen they need by eating plants, by eating other animals that ate plants, or by eating animals that ate animals that ate plants.
plants and animals
Plant obtain their food from the sun. The process is called photosynthesis. Animals obtain their food from animals or plants.