Which of the following nutrient cycles has its largest reservoir in the atmosphere?
A. Carbon cycle
B. Nitrogen cycle
C. Potassium cycle
D. Phosphorus cycle
E. Water cycle
Answer (2)
The nutrient cycle with its largest reservoir in the atmosphere is the Nitrogen cycle. The atmosphere contains approximately 78% nitrogen gas (N₂), making it the principal reservoir for nitrogen. Nitrogen is essential for all living organisms as it is a major component of amino acids, which are the building blocks of proteins, and nucleic acids like DNA and RNA.
In contrast, other cycles such as the Carbon cycle have significant reservoirs in both the atmosphere (as carbon dioxide) and the ocean, and the Phosphorus cycle primarily cycles through rocks and sediments without an atmospheric component. The Water cycle also has a large atmospheric component through processes like evaporation and precipitation, but it is not the largest compared to the nitrogen reservoir.
The Nitrogen cycle has its largest reservoir in the atmosphere, with nitrogen gas (N₂) making up about 78% of the air. This cycle involves processes like nitrogen fixation, nitrification, assimilation, ammonification, and denitrification that allow nitrogen to move through the environment. Therefore, the correct option is B - Nitrogen cycle.
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