Generally, animals ingest nitrogen when they consume plants. Animals get the nitrogen their body need by consuming plants. It can be a part of the body of the animal or be broken down and be excreted as waste product in the form of urea in the urine. When the animal die, decomposition will take place to bring back the nitrogen into the environment. Plants are able to use the released nitrogen when bacteria modify the form of the nitrogen in the process of decomposition.
Answer - Option 2 - animals, plants