Which biogeochemical cycle does not involve a stage where the chemical enters the atmosphere?

• A. Phosphorus cycle
• B. Nitrogen cycle
• C. Water cycle
• D. Carbon cycle

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of biogeochemical cycles. These are pathways through which elements or compounds move through the Earth's systems, including the atmosphere, hydrosphere, lithosphere, and biosphere.
2. Step 2: Review the characteristics of the phosphorus cycle. Unlike other cycles, the phosphorus cycle does not involve a gaseous phase where phosphorus enters the atmosphere. It primarily occurs in the lithosphere and hydrosphere.
3. Step 3: Compare the phosphorus cycle to other cycles listed in the problem. For example, the nitrogen cycle includes nitrogen gas in the atmosphere, the water cycle involves water vapor in the atmosphere, and the carbon cycle includes carbon dioxide in the atmosphere.
4. Step 4: Identify the key difference: the phosphorus cycle is unique because it lacks a stage where the chemical enters the atmosphere, making it distinct from the nitrogen, water, and carbon cycles.
5. Step 5: Conclude that the correct answer is the phosphorus cycle, as it does not involve a stage where the chemical enters the atmosphere, unlike the other cycles mentioned.