Nitrogen Cycle Worksheet
A Grade 9 science worksheet covering the key processes and components of the nitrogen cycle.
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Nitrogen Cycle Worksheet
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Read each question carefully and answer to the best of your ability. Refer to the diagram of the Nitrogen Cycle below.
1. Which process converts atmospheric nitrogen (N₂) into ammonia (NH₃) or ammonium (NH₄⁺)?
Nitrification
Denitrification
Nitrogen Fixation
Ammonification
2. Which organisms are primarily responsible for converting nitrites (NO₂⁻) to nitrates (NO₃⁻) in the soil?
Denitrifying bacteria
Nitrogen-fixing bacteria
Nitrifying bacteria
Decomposers
3. The process by which plants absorb nitrates from the soil is called .
4. When organisms die, decomposers convert organic nitrogen back into ammonia through a process called .
5. Atmospheric nitrogen (N₂) can be directly used by most plants and animals.
True
False
6. Denitrification is the process that returns nitrogen gas to the atmosphere.
True
False
7. Explain the importance of nitrogen-fixing bacteria in the nitrogen cycle.
8. Describe one human impact on the nitrogen cycle and its potential consequences.