Use your understanding of the phosphorus cycle to answer the questions provided.
phosphorus cycles between living things and the ?

Phosphorus cycles between living things and the environment, particularly the soil. This is the case with many other substances as well such as carbon. The cycling occurs due to the action of organisms which uptake and release phosphorus into the soil. Phosphorus exists in animals in many forms, particularly in the ATP molecule. When the animal dies, its remains are decomposed and the constituent ions are released into the soil, after which they are taken up by plants. Animals consuming these plants gain the phosphorus again, and the cycle continues.

Pro insulin undergoes extensive posttranslational modification along the production pathway .