What is the energy source of energy for chemosynthesis

Ferrous ions ( chemical ) : are the energy source for chemosynthesis

Chemosynthesis is the process of converting carbon-containing molecules ( CO₂ ) into organic matter, through the oxidation of inorganic matter which serves as a source of energy during this process.  

During chemosynthesis the use of sunlight as a source of energy is non existent rather chemicals such as Ferrous ions or inorganic matter are used as a source of energy for the process.

Hence we can conclude that Chemicals such as ferrous ions are the energy source for chemosynthesis

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