Chromosomes occur in pairs (in most somatic cells) since one member of each pair comes from the mother and the other from the father. In most prokaryotes, the chromosome is usually a circular strand of DNA; hence, the entire genome is carried on only one chromosome.
Thus, an average diet of 1,900 calories per day would dictate an intake of 1,900 ml (approximately 64 ounces) of water. However, people interpreted this as a recommendation to drink 1,900 ml of pure water, forgetting the fact that water is also found in abundance in the other liquids and foods we consume.
Everyone has heard the advice, Drink eight 8-ounce glasses of water a day.. That's about 1.9 liters, which isn't that different from the Institute of Medicine recommendations. Although the 8 by 8 rule isn't supported by hard evidence, it remains popular because it's easy to remember.