Which of the following microorganisms is used for the production of citric acid in the industry? MCQ with Answer and Explanation

Explanation:
Kingdom Protista includes diverse unicellular eukaryotes like protozoans, slime molds, and unicellular algae. They can be autotrophic, heterotrophic, or mixotrophic. Monera contains prokaryotes, Fungi are multicellular eukaryotes (except yeast) with absorptive nutrition, Plantae are multicellular autotrophs. Protista is a paraphyletic group in modern cladistics but used in the five-kingdom system.

Explanation:
Iodine is essential for synthesis of thyroxine (T₄) and triiodothyronine (T₃). Deficiency leads to enlargement of the thyroid gland, known as goiter, as the gland tries to compensate. Anemia is due to iron deficiency, rickets to vitamin D deficiency, scurvy to vitamin C deficiency. Iodized salt is a public health measure to prevent goiter.

Explanation:
Anabaena azollae is a heterocystous cyanobacterium that lives symbiotically in the dorsal leaf cavities of the water fern Azolla. It fixes atmospheric nitrogen, providing a natural nitrogen source for rice paddies when Azolla is used as green manure. Nostoc is free-living or lichen symbiont, Rhizobium and Azotobacter are bacteria.