Nutrient Cycling MCQs (Quiz 11)

1. The weathering of rocks contributes directly to ___________________

Soil formation and nutrient release

Formation of humus

Atmospheric circulation

Development of food chains

2. A plant growing in nitrate-rich soil absorbs NO₃⁻ through its roots. Which sequence correctly represents what happens during assimilation?

NO₃⁻ is broken down into CO₂ and water during respiration

NO₃⁻ is reduced and incorporated into organic molecules such as amino acids, proteins, and nucleic acids

NO₃⁻ is converted to N₂ and expelled through stomata

NO₃⁻ is released back into the soil after absorption

3. Which environmental factor has the greatest influence on weathering rates?

Magnetic field strength

Population density

Climate

Longitude

4. An increase in atmospheric CO₂ enhances the greenhouse effect because CO₂ ________________

Reflects all incoming solar radiation

Converts oxygen into ozone

Prevents evaporation from oceans

Absorbs and re-emits outgoing infrared radiation

5. Which mineral dissolves most readily in pure water?

Feldspar

Halite

Mica

Quartz

6. Which of the following correctly describes denitrification?

Conversion of atmospheric N₂ into ammonia by soil bacteria

Oxidation of ammonium ions into nitrites and nitrates

Breakdown of proteins into ammonium ions by decomposers

Reduction of nitrates into nitrogen gas by anaerobic bacteria

7. A tropical rainforest has a very high nutrient turnover rate despite having nutrient-poor soil. What best explains this?

Rapid decomposition and immediate uptake by plant roots recycle nutrients so efficiently that little accumulates in the soil

Slow decomposition allows gradual accumulation of nutrients in the soil

Frequent rainfall dissolves rock minerals, replenishing soil nutrients rapidly

Nutrients are imported constantly from surrounding ecosystems via rivers

8. Which gas released during decomposition of organic matter in waterlogged soils is a potent greenhouse gas?

Oxygen gas (O₂)

Nitrogen gas (N₂)

Carbon dioxide (CO₂)

Methane (CH₄)

9. Which of the following correctly describes the role of nitrogen fixation in the nitrogen cycle?

It converts nitrates into nitrogen gas, returning it to the atmosphere

It oxidizes ammonium ions into nitrites and nitrates for plant uptake

It reduces atmospheric N₂ into ammonia, making nitrogen available to living organisms

It breaks down proteins in dead organisms into ammonium ions

10. A plant growing in phosphorus-poor soil still thrives because of a fungal partner that extends far into the soil to absorb nutrients on its behalf. What is this fungal partner called __________________

Nitrosomonas

Rhizobium

Mycorrhizal fungi

Azotobacter

Question 1 of 10

Nutrient Cycling MCQs (Quiz 11)

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