What is the gas ration in the atmosphere?

Which property is the basis for the division of the atmosphere into several regions? How do you know when it is day time or night time in space? The constellation that contains the polestar? Where are the Medician stars found? When can you see the Aurora Borealis and the Aurora Australis? How many mountains is there on mercury? What is the warmest planet and cloudy planet? What is Neptune's diameter compared with earth? What would happen to the length of the day if you had no atmosphere? Effects of space exploration on environment? How old would you be on mars if you are 14? Which woman has stayed in space for longest time? Period due today but no signs of it? What was the weather on the day when Apollo 11 left earth? What was Apollos Rivoire's wife's name? Who was the second man to walk moon? How is the age of the Sun determined? Is planet a long or short vowel sound? Why did neil Buchanan died? What words unscramble sundial in a word?