The check digit is used to confirm the initial digits of the card number. The benefits of using a checksum is that it prevents casual attempts to invent credit card numbers, as only one in ten will be valid.
Length (adj). the longest, or longer, dimension of any object, in distinction from breadth or width; extent of anything from end to end; the longest line which can be drawn through a body, parallel to its sides; as, the length of a church, or of a ship; the length of a rope or line.
glutaminyl=C5H9N2O2 valyl=(CH3)2CHCH(NH2)CO} Therefore one strand of DNA could be lengthened out to an infinite amount of letters long. The current longest accepted word in English dictionaries (above) is questioned also being as that it was coined by a man in 1935 simply for the purpose of creating a new longest word.