
The three doshas (weaknesses) and their antidotes are the basis of Ayurvedic medicine in India. In European alchemy, the three primes (Latin: tria prima) were salt (), sulfur () and mercury (). Humans being trichromatic, the retina contains three types of color receptor cells, or cones. The ability of the human eye to distinguish colors is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. For this reason it is widely utilized in construction, engineering and design. The triangle, a polygon with three edges and three vertices, is the most stable physical shape. Humans perceive the universe to have three spatialdimensions, but some theories, such as string theory, suggest there are more. Three is the number of dimensions that humans can perceive. Three is the ASCII code of 'End of Text'.The Roman numeral III stands for giant star in the Yerkes spectral classification scheme.
List of basic calculations Multiplication This is most likely based on the prevalence of this phenomenon among people in such disparate regions as the deep Amazon and Borneo jungles, where western civilization's explorers have historical records of their first encounters with these indigenous people. Early peoples had a word to describe the quantities of one, two, and three but any quantity beyond was simply denoted as 'Many'.
There is some evidence to suggest that early man may have used counting systems which consisted of 'One, Two, Three' and thereafter 'Many' to describe counting limits.