Comprehension:
An ecosystem is a structural and functional unit of nature, which comprises of both abiotic (e.g., air, water, soil) and biotic (e.g., producers, consumers, decomposers) components. Productivity, decomposition, energy flow and nutrient cycling are four key important processes in an ecosystem. Primary productivity is rate of capture of solar energy or biomass production by producers. The energy flow is unidirectional and plants can utilize only 1% of available solar energy and energy is transferred among trophic level, following 10% law. The rate of capture of solar energy or total production of biomass by producers is called as gross primary productivity. The energy left after utilisation by producers is called as net primary productivity. Rate of assimilation of food energy by the consumers is referred as secondary productivity. Decomposition processes such as fragmentation of detritus, leaching and catabolism are responsible for converting detritus into CO2, H2O and inorganic nutrients.
Which of the following is not a process of detritus decomposition into CO2, H2O and nutrients?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Chemical reduction
The passage names the decomposition processes as fragmentation of detritus, leaching and catabolism. Fragmentation is the physical breakdown of detritus by detritivores, leaching washes water-soluble nutrients into the soil, and catabolism is the enzymatic breakdown of detritus into simpler inorganic substances.
Chemical reduction is not one of these steps. Decomposition is an oxidative, aerobic process, completed by humification and mineralisation, so a reduction reaction does not describe it.