To make white sugar, sulfur dioxide is added to cane juice before it gets evaporated. This gas does the bleaching of the juice so that it does not turn brown and produces white sugar. At later stages, phosphoric acid, calcium hydroxide or carbon dioxide is added to absorb impurities.
The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep.
Given this much, we now know why we sleep. The average adult sleeps 7 to 8.6 hours a day. Children sleep more than adults; they spent about 10 hours a day sleeping. Newborns, however, may sleep for nearly two-thirds of their day. There is an age-related difference in average time spent sleeping. As a person ages, they require less sleep. The elderly only spent around 6.5 hours a day sleeping.