How are the carbon and nitrogen cycle similar A neither one is used by living organism to make proteins B both require bacteria to convert gases to usable forms C neither has an important role in the environment D both recycle matter

The correct answer is **D both recycle matter**.

Both the carbon and nitrogen cycles are essential biogeochemical cycles that recycle matter in the environment. They involve various processes that transform elements into different chemical forms, allowing them to be reused by living organisms. While they have unique processes and organisms involved, the fundamental concept of recycling matter is a key similarity between the two cycles.