The correct option is Yeast.
Explanation
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In the context of cellular respiration, it is the incomplete oxidation of glucose under anaerobic conditions (absence of oxygen). Alcoholic fermentation specifically converts sugars into ethyl alcohol (ethanol) and carbon dioxide.
Option Analysis
- Yeast Yeast: Correct. Yeast, particularly the species Saccharomyces cerevisiae (often called Brewer’s yeast), is a unicellular fungus. It is widely used in the brewing and baking industries because it performs alcoholic fermentation. In this process, yeast breaks down glucose to produce ethanol and carbon dioxide as by-products.
- Amoeba Amoeba: Incorrect. Amoeba is a unicellular protozoan found in freshwater. It primarily relies on aerobic respiration, absorbing dissolved oxygen from water through its cell membrane via diffusion.
- Paramoecium Paramoecium: Incorrect. Paramoecium is also a unicellular protozoan. Like Amoeba, it utilizes aerobic respiration to generate energy and does not perform industrial-scale fermentation.
- Hydra Hydra: Incorrect. Hydra is a multicellular organism belonging to the phylum Cnidaria. It exchanges gases (oxygen and carbon dioxide) directly with the surrounding water through its body surface (aerobic respiration).
Key Takeaway: Yeast (Saccharomyces cerevisiae) is the primary organism used in industrial fermentation to convert glucose into ethanol and carbon dioxide under anaerobic conditions.