An example of MS-DOS's command-line interface, this one showing that the current directory is the root of drive C. MS-DOS (/ËÉmÉsËdÉs/ EM-es-DOSS; acronym for Microsoft Disk Operating System) is a discontinued operating system for x86-based personal computers mostly developed by Microsoft.
Written by: Kierstan Boyd. Nov. 08, 2012. The main symptom of vitamin A deficiency is vision loss and blindness. Vision loss often begins as a problem adjusting to seeing in the dark, or night blindness. People with night blindness do not see well in the dark, but are able to see normally if enough light is present.
Definitions of Vitamin A deficiency: Condition due to a deficiency of vitamin A. - (Source-Diseases Database). Vitamin A deficiency is listed as a  rare disease  by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH).This means that Vitamin A deficiency, or a subtype of Vitamin A deficiency, affects less than 200,000 people in the US population.efinitions of Vitamin A deficiency: Condition due to a deficiency of vitamin A. - (Source-Diseases Database). Vitamin A deficiency is listed as a  rare disease  by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH).