The correct answer is b) Phosphorus.
Phosphorus is an essential element for living organisms, primarily involved in energy transfer and the formation of DNA and RNA. Unlike nitrogen, carbon, and oxygen, which are all gaseous and can enter and exit the atmosphere, phosphorus primarily exists in solid forms, such as phosphates, and does not have a significant gaseous state. It cycles through the soil, water, and living organisms but does not cycle through the air in a meaningful way. Therefore, while nitrogen, carbon, and oxygen constantly circulate through the atmosphere and various ecosystems, phosphorus remains largely bound to land and aquatic systems.