Nutrient Cycling MCQs (Quiz 11)

1. Which of the following correctly describes denitrification?

Reduction of nitrates into nitrogen gas by anaerobic bacteria

Oxidation of ammonium ions into nitrites and nitrates

Conversion of atmospheric N₂ into ammonia by soil bacteria

Breakdown of proteins into ammonium ions by decomposers

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

It breaks down proteins in dead organisms into ammonium ions

It oxidizes ammonium ions into nitrites and nitrates for plant uptake

3. 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 __________________

Mycorrhizal fungi

Rhizobium

Nitrosomonas

Azotobacter

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

Reflects all incoming solar radiation

Prevents evaporation from oceans

Converts oxygen into ozone

Absorbs and re-emits outgoing infrared radiation

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

NO₃⁻ is released back into the soil after absorption

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

NO₃⁻ is broken down into CO₂ and water during respiration

NO₃⁻ is converted to N₂ and expelled through stomata

6. The weathering of rocks contributes directly to ___________________

Development of food chains

Soil formation and nutrient release

Formation of humus

Atmospheric circulation

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

Climate

Magnetic field strength

Longitude

Population density

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

Nitrogen gas (N₂)

Methane (CH₄)

Carbon dioxide (CO₂)

Oxygen gas (O₂)

9. Which mineral dissolves most readily in pure water?

Quartz

Feldspar

Halite

Mica

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

Slow decomposition allows gradual accumulation of nutrients in the soil

Frequent rainfall dissolves rock minerals, replenishing soil nutrients rapidly

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

Nutrients are imported constantly from surrounding ecosystems via rivers

Question 1 of 10

Nutrient Cycling MCQs (Quiz 11)

Leave a Reply Cancel reply

Notes

Welcome to Agro-Publishers