: 11 The later definition by Cavalli-Sforza & Bodmer (1971) is currently used: Genetic polymorphism is the occurrence in the same population of two or more alleles at one locus, each with appreciable frequency, where the minimum frequency is typically taken as 1%.
The financial world splits up its calendar into four quarters, each three months long. If January to March is the first quarter, April to June is the second quarter, and so on, though a company's first quarter does not have to begin in January.
In 3 months there are 3 times 4 weeks, which is 12 weeks. Therefore there are 12 weeks in a quarter.   CORRECTION   There are thirteen weeks in a quarter of a year. 52 wks per yr divided by 4 is the accepted method to determine how many weeks per quarter.