Answer:
The answer is all of the above are correct.
Step-by-step explanation:
Chemosynthesis occurs in bacteria and other organisms and involves the use of energy released by inorganic chemical reactions to produce food. All chemosynthetic organisms use energy released by chemical reactions to make a sugar, but different species use different pathways. For example, at hydrothermal vents, bacteria oxidize hydrogen sulfide and add carbon dioxide and oxygen to produce sugar, sulfur, and water:
CO2 + 4H2S + O2 ⇒ CH20 + 4S + 3H2O.
Chemosynthesis is the process by which food (glucose) is made by bacteria using chemicals as the energy source, rather than sunlight. Chemosynthesis occurs around hydrothermal vents and methane seeps in the deep sea where sunlight is absent. During chemosynthesis, bacteria living on the seafloor or within animals use energy stored in the chemical bonds of hydrogen sulfide and methane to make glucose from water and carbon dioxide (dissolved in seawater). Pure sulfur and sulfur compounds are produced as by-products.