Answer:
C. Soil
Explanation:
The choice with variable composition is the soil. Soil have many different composition.
- Soil is made up of minerals, organic matter , water and soil air.
- Soil minerals are derived from weathered bedrock materials that have been broken down into small pieces.
- Organic matter is derived from dead and decaying materials from plants and animals.
- All these materials combine together to form a soil.
When sulfate (SO₄²⁻) serves as the electron acceptor at the end of a respiratory electron transport chain, the product is hydrogen sulfide (H₂S).
How sulfate acts as electon acceptor and electron donor?
- Sulfate (SO₄²⁻) is used as the electron acceptor in sulfate reduction, which results in the production of hydrogen sulfide (H2S) as a metabolic byproduct.
- Many Gram negative bacteria identified in the -Proteobacteria use sulfate reduction, which is a rather energy-poor process.
- Gram-positive organisms connected to Desulfotomaculum or the archaeon Archaeoglobus also utilise it.
- Electron donors are needed for sulfate reduction, such as hydrogen gas or the carbon molecules lactate and pyruvate (organotrophic reducers) (lithotrophic reducers).
Learn more about the Electron transport chain with the help of the given link:
brainly.com/question/24372542
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The answer is D :) have a nice day!
