NDEM2 S2 recap question

Which of the following best describes how human activities have fundamentally disrupted the natural carbon cycle?

• Increasing photosynthetic rates through global reforestation
• Releasing long-sequestered carbon through fossil fuel combustion and deforestation
• Enhancing natural carbon absorption mechanisms
• Stabilizing atmospheric carbon concentrations

In the nitrogen cycle, why can't most organisms directly utilize atmospheric nitrogen (N₂)?

• It lacks chemical reactivity
• Its triple covalent bond requires significant energy to break
• It is too heavy for biological processes
• It oxidizes too quickly in the atmosphere

Which process most directly transforms atmospheric nitrogen into biologically available forms?

• Denitrification
• Nitrification
• Nitrogen fixation
• Ammonification

How do decomposers fundamentally contribute to nutrient cycling?

• By preventing organic matter breakdown
• By converting complex organic molecules into simpler, recyclable forms
• By storing nutrients permanently
• By generating new organic compounds

What ecological consequence emerges from excessive synthetic nitrogen fertilizer use?

• Increased crop productivity without environmental impact
• Potential eutrophication of aquatic ecosystems
• Enhanced soil microbial diversity
• Reduced greenhouse gas emissions

Which reservoir stores the largest proportion of Earth's carbon?

• Atmosphere
• Terrestrial biosphere
• Oceans
• Sedimentary rocks

What mechanism allows plants to transfer atmospheric carbon into biological systems?

• Respiration
• Photosynthesis
• Decomposition
• Combustion

How do volcanic eruptions impact the global carbon cycle?

• By permanently removing carbon from circulation
• By releasing stored carbon dioxide into the atmosphere
• By converting carbon into inert compounds
• By accelerating photosynthetic processes

Which bacterial process converts nitrates back into atmospheric nitrogen?

• Nitrogen fixation
• Nitrification
• Denitrification
• Ammonification

What distinguishes anthropogenic disruptions of biogeochemical cycles from natural variations?

• Rate of change
• Total quantity of elemental transfer
• Geographical distribution
• Molecular complexity