Nitrogen and phosphorus are important for living things and can limit how much they can grow. They play different roles in plants and other organisms. Some parts of cells need nitrogen and phosphorus, while others can use different elements. The amount of nitrogen and phosphorus in organisms can change, making it hard to understand how they are used. Where an organism lives can affect how much nitrogen and phosphorus it has. Organisms can make special enzymes to help them get nitrogen and phosphorus from their environment. These enzymes help change hard-to-use forms of nitrogen and phosphorus into forms that can be used.