Final answer:
The correct answer to the question is C) Archaea. These prokaryotic organisms are known for their ability to thrive in extreme conditions and for their role in anaerobic respiration, particularly by the group called methanogens.
Step-by-step explanation:
The organisms that commonly colonize the hot acid of volcanic springs, the airless depths of marine sediments, the sludge of sewage treatment plants, the pools beneath the frozen surface of Antarctica, as well as the acidic, oxygen-free environment of a cow's stomach where they break down ingested cellulose and generate methane gas, are the Archaea. These prokaryotic microorganisms are known for their ability to thrive in extreme environments and are distinguishable from bacteria in their genetics, biochemistry, and ecological roles. A particular group of Archaea known as methanogens is responsible for reducing carbon dioxide to methane in the process of anaerobic respiration, which plays a significant role in various ecosystems including the digestion process in ruminants like cows. Moreover, methanogens are potential candidates for life on other planets, such as Mars, due to their unique metabolic abilities.