Chemical Engineering The primary role of vitamin D is to maintain normal blood levels of calcium and phosphorus. Also, vitamin D helps the body absorb calcium that forms and maintains strong bones. Although most foods do not contain substantial amounts of vitamin D, some food sources do contain the precursors that the body needs in order to synthesize vitamin D. Ergosterol is found in many vegetables and 7-dehydrocholestrol is present in fish and dairy products. When ergosterol and 7-dehydrocholestrol, which are stored under the skin, are exposed to sunlight, these precursors are converted into ergocalciferol and cholecalciferol, respectively. The precursors are converted into vitamin D via two successive pericyclic reactions. Provide a plausible mechanism for these transformations: (India) Accessibility: Unavailable Recovered DOLL