How many hours does a 12 year old have to sleep?

At these ages, with social, school, and family activities, bedtimes gradually become later and later, with most 12-years-olds going to bed at about 9 p.m. There is still a wide range of bedtimes, from 7:30 to 10 p.m., as well as total sleep times, from 9 to 12 hours, although the average is only about 9 hours

                                                        water

a colorless, transparent, odorless, tasteless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms.

                                                        halon  

any of a number of unreactive gaseous compounds of carbon with bromine and other halogens, used in fire extinguishers, but now known to damage the ozone layer.

                                                  dry chemical

extinguishing agent used on class a, class b, and class c fires.

                                                  carbon dioxide

a colorless, odorless gas produced by burning carbon and organic compounds and by respiration. it is naturally present in air (about 0.03 percent) and is absorbed by plants in photosynthesis.