Nutrient Cycling MCQs (Quiz 13)

1. Which process removes carbon dioxide directly from the atmosphere and stores it in plant biomass?

Respiration

Photosynthesis

Fermentation

Combustion

2. Ecological succession following a volcanic eruption depends heavily on _______________

Weathering of volcanic material

All of these

Nutrient accumulation

Soil development

3. Denitrification is most likely to occur under which soil conditions, and what type of bacteria carry it out?

Well-aerated soils; autotrophic nitrifying bacteria

Waterlogged, anaerobic soils; anaerobic bacteria such as Pseudomonas

Waterlogged soils; nitrogen-fixing bacteria such as Rhizobium

Dry sandy soils; aerobic decomposers

4. What is the primary contribution of decomposers to nutrient cycling in an ecosystem?

Synthesizing complex proteins that are passed on to consumer organisms

Breaking down dead organic matter and releasing inorganic nutrients back into the soil and water

Converting solar energy into chemical energy stored in organic molecules

Absorbing carbon dioxide from the atmosphere for use in biosynthesis

5. Which soil and nutrient combination would be most vulnerable to leaching losses?

Clay soil with phosphate ions, in a dry climate

Sandy soil with nitrate ions, under heavy and frequent rainfall

Loam soil with potassium ions, under seasonal drought conditions

Peat soil with ammonium ions, under moderate rainfall

6. The principal reservoir of nutrients in sedimentary cycles is the ______________

Lithosphere

Biosphere

Atmosphere

Hydrosphere

7. A farmer applies excess ammonium-based fertilizer to a well-aerated field. Over time, crop yield declines due to nitrogen loss. Which process is most directly responsible, and what is its first step?

Denitrification, beginning with the reduction of NH₄⁺ to N₂

Ammonification, beginning with the breakdown of NH₄⁺ into organic nitrogen

Nitrogen fixation, beginning with the conversion of N₂ into NH₃

Nitrification, beginning with the oxidation of NH₄⁺ to NO₂⁻, making nitrogen more susceptible to leaching

8. Which nutrient cycle is least dependent on volcanic activity?

Carbon cycle

Sulfur cycle

Nitrogen cycle

Phosphorus cycle

9. Fresh volcanic deposits are gradually incorporated into nutrient cycles primarily through _____________

Respiration and weathering processes

Weathering and decomposition processes

Denitrification and decomposition processes

Photosynthesis and decomposition processes

10. Weathering contributes to nutrient cycling by ___________________

Reducing soil fertility

Locking nutrients permanently in rocks

Making mineral nutrients available to ecosystems

Preventing mineral release

Question 1 of 10

Nutrient Cycling MCQs (Quiz 13)

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