Which cycle includes processes such as nitrogen fixation, nitrification, and denitrification?

Which cycle includes processes such as nitrogen fixation, nitrification, and denitrification?

• A. Nitrogen Cycle
• B. Carbon Cycle
• C. Soil
• D. Desert Pavement

Answer: (A)

The nitrogen cycle describes how nitrogen moves through the environment, cycling among the atmosphere, soil, water, and living organisms. Nitrogen fixation is the process by which certain bacteria convert atmospheric N2 into ammonia (NH3) or ammonium (NH4+), making nitrogen usable for plants. Nitrification then changes that ammonia first into nitrite (NO2-) and then into nitrate (NO3-), which plants can take up as a nutrient. Denitrification reverses part of the process by converting nitrate back into atmospheric N2 (and some N2O) under low-oxygen conditions, returning nitrogen to the air and closing the cycle. This set of transformations is unique to nitrogen and is crucial because most organisms cannot use atmospheric N2 directly; the cycle provides the nutrient forms that living things need to grow. The carbon cycle, soil as a material, and desert pavement are not cycles describing these nitrogen transformations.

The nitrogen cycle describes how nitrogen moves through the environment, cycling among the atmosphere, soil, water, and living organisms. Nitrogen fixation is the process by which certain bacteria convert atmospheric N2 into ammonia (NH3) or ammonium (NH4+), making nitrogen usable for plants. Nitrification then changes that ammonia first into nitrite (NO2-) and then into nitrate (NO3-), which plants can take up as a nutrient. Denitrification reverses part of the process by converting nitrate back into atmospheric N2 (and some N2O) under low-oxygen conditions, returning nitrogen to the air and closing the cycle. This set of transformations is unique to nitrogen and is crucial because most organisms cannot use atmospheric N2 directly; the cycle provides the nutrient forms that living things need to grow. The carbon cycle, soil as a material, and desert pavement are not cycles describing these nitrogen transformations.