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Which of the following is a type of chemoautotroph.
A. Sulphur bacteria, Beggiatoa thiobacillus
B. Iron bacteria, Ferrobacillus
C. Leptothrix
D. All of the above

Answer Verified Verified
Hint:Chemoautotrophs are those organisms which derive their energy by oxidation of various inorganic substances such as nitrates, nitrites and ammonia. They use this energy for ATP production; chemoautotrophs play a great role in recycling nutrients like nitrogen, phosphorus, iron and sulphur.

Complete answer:
A. Sulphur bacteria, Beggiatoa thiobacillus-Beggiatoa is filamentous bacteria, it is colourless, sulphur-storing bacteria. They live by the oxidation of sulphide with oxygen or nitrate. They are benthic organisms which occur in freshwater and marine water, where sulphur is present.
B. Iron bacteria, Ferrobacillus- They derive energy by oxidizing dissolved ferrous ions and are chemoautotrophs.
C. Leptothrix- It belongs to the genus of gram-negative bacteria. They also withdraw their energy from inorganic substances.

The correct option is D- All the above.

Additional information:(i) Chemoautotrophs are commonly found in environments where plants cannot survive, such as at the bottom of the ocean or in acidic hot springs.
(ii) Chemoautotrophs form the basis of the energy pyramid for ecosystems where photosynthesizers cannot survive.
(iii) Without them life would only be able to exist where energy could be derived from sunlight.

Note:The most common type of Chemotrophic organisms are prokaryotic and include both bacteria and fungi.All these chemotrophic organisms require carbon to survive and reproduce.