Which gas forms 21% of Earth's atmosphere?

Separated the laws of islam from the laws of the nationreplaced the old muslim calender with the gregorian calender  abolished religious courts and created a new legal system based on european law as opposed to the previous system based on the islamic law code granted women the right to vote and to hold public office launched government-funded programs to industrialize turkey and to spur the economic growth attempted to modernize turkey by banning the fez which was of greek origin marriage was considered civil and not religious and polygamy was abolished women were given the right to vote in all elections 

Ibelieve the answer would be a large-scale natural disaster 

The answer would be a.